Windows 11 KB5077181: Severe Boot Loops & Security Risks

Critical February 2026 security updates are causing infinite restart cycles and network failures on Windows 11 24H2 and 25H2 systems.

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Hook & Who This Is For (Intro)

How to identify and resolve critical startup failures after the February 2026 security update.

You may have recently updated your Windows 11 PC only to find it trapped in an endless cycle of restarts that never reaches the desktop ^[2][4][13]. Reports indicate that some systems reboot more than 15 times consecutively, effectively locking users out of their devices ^[1][4][14]. If you are facing sudden login failures or a total loss of internet connectivity following the latest patch, you are not alone in experiencing these stability regressions ^[6][7][15].

This guide is for Windows 11 users and IT administrators currently managing versions 24H2 or 25H2 who have installed or are prompted to install update KB5077181 ^[4][11][13]. We cover the identification of specific boot loop symptoms, common error codes like 0x800f0983, and manual uninstallation steps for unbootable systems ^[1][5][12]. This report does not cover issues related to older versions of Windows 10 or hardware-specific failures unrelated to the February 10, 2026, update cycle ^[2][7][11].

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Who This Is For

• Affected Users: Anyone whose PC is stuck in a restart loop or seeing System Event Notification Service (SENS) errors at sign-in ^[1][2][11].
• System Versions: Specifically those running Windows 11 build 26100.7840 or 26200.7840 ^[4][12][13].
• Network Issues: Users who are "Connected, no internet" due to DHCP failures immediately following a restart ^[1][4][14].
• Exclusions: This does not apply to users on Windows 11 version 23H2 or earlier, as those versions use different update packages ^[4][7][13].

TL;DR / What This Means for You

The February 2026 cumulative update for Windows 11 is presenting a difficult choice for users: critical security protection versus potential system instability. Here are the key takeaways from the current situation:

• System Stability Risks: The KB5077181 update is linked to reports of infinite restart loops and installation failures on certain devices ^[4][19]. Users have specifically identified error codes 0x800f0983 and 0x800f0991 during failed attempts to apply the patch ^[4].
• Critical Security Fixes: This release is highly significant as it addresses 58 vulnerabilities, including six actively exploited zero-day flaws ^[1][16]. Notable fixes include CVE-2026-20841, a remote code execution vulnerability in Notepad, and CVE-2026-21533, an elevation of privilege flaw in Remote Desktop Services ^[4][16].
• Targeted Systems: Issues appear most prevalent on Windows 11 versions 24H2 and 25H2, specifically builds 26200.7840 and 26100.7840 ^[4][9]. While many home users may install it automatically, technical experts recommend that managed environments validate the update on a small subset of hardware first ^[6][14].
• Recovery Options: If a system becomes unbootable, the update can potentially be removed through the Windows Recovery Environment using the Command Prompt with the string wusa /uninstall /kb:5077181 /quiet /norestart ^[4].
• Risk Note: While delaying the update avoids the immediate risk of a boot loop, it may leave the system exposed to "one-click" execution vulnerabilities and other actively exploited threats ^[5][16]. There is currently no method that is guaranteed to be 100% safe for all hardware configurations ^[14].

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Key Sources (Quick Links)

• Users report install errors and system bugs after Windows 11’s Feb update ^[1]
• February's Windows 11 update is causing startup problems for users ^[2]

Background / Basics

On February 10, 2026, Microsoft released KB5077181 as part of its monthly "Patch Tuesday" cycle ^[1][4][11]. This cumulative update was designed to provide essential security fixes and quality improvements for Windows 11 ^[4][11]. It specifically targets the latest versions of the operating system, including Version 24H2 (Build 26100.7840) and Version 25H2 (Build 26200.7840) ^[4][7][8].

The update addresses a total of 58 vulnerabilities across various Windows components ^[4][11]. These include six zero-day vulnerabilities—flaws that were already known or being actively exploited before a patch was available—listed in CISA’s Known Exploited Vulnerabilities catalog ^[1][4][11]. Key security focuses of the update include:

• Elevation of Privilege: Fixing flaws in the Desktop Window Manager and Remote Desktop Services ^[4][7][11].
• Remote Code Execution: Patching a vulnerability in Notepad related to Markdown files ^[4][7][11].
• Security Feature Bypass: Addressing a Windows Shell issue that could allow SmartScreen evasion ^[4][11].

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Secure Boot and Future-Proofing

Beyond standard security patches, KB5077181 includes critical updates for Secure Boot certificates ^[4][11]. Microsoft is currently transitioning devices to newer 2023 certificates because many 2011-era certificates are set to expire in June 2026 ^[4][5][12].

If these certificates are not updated, affected devices may enter a degraded security state or fail to boot properly once the old certificates expire ^[2][5]. This update also carries forward improvements from previous releases, such as KB5074109, while addressing specific issues like gaming eligibility and WPA3 Wi-Fi connectivity ^[4][7][11].

Technical Detail	Information
KB Number	KB5077181 [4][7]
Release Date	February 10, 2026 [4][11]
Affected Builds	26100.7840, 26200.7840 [4][7][8]
Primary Goal	Security patches and Secure Boot updates [4][11][13]

While cumulative updates are typically routine, they modify core system files and the servicing stack, which is the component that installs other updates ^[4][5]. When incompatibilities occur between these updates and specific hardware or drivers, it can lead to significant stability regressions ^[4][9].

Problem Explanation (What's Going On?)

The Windows 11 February 2026 cumulative update, identified as KB5077181, is reportedly causing severe stability issues and installation failures for a growing number of users ^[2][7]. While the update was intended to provide routine fixes, reports indicate it can lead to critical system instability or prevent devices from reaching the desktop entirely ^[2][9].

Primary Symptoms and Errors

The issues typically begin during the installation phase or immediately following the required system restart ^[1][7]. Users have documented a range of specific symptoms that disrupt standard PC operations:

• Installation Failures: Many users report that the update process hangs or fails to complete, returning error codes such as 0x800F0991, 0x800F0983, 0x800F0922, 0x80073712, and 0x80096004 ^[1][2].
• Infinite Boot Loops: This is the most critical symptom, where the PC enters an endless cycle of restarts ^[7][9]. In these cases, users are often unable to access the login screen or the operating system ^[9].
• Network Failure: On systems where the update successfully installs, Wi-Fi connectivity often breaks ^[1]. Devices may show a "connected" status but have no internet access due to DHCP errors ^[1][2].
• Service Errors: Some users encounter a SENS (System Event Notification Service) error message during startup ^[7]. This typically indicates the system cannot interact with core services because of missing data or underlying network problems ^[9].

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Impact and Prevalence

While Microsoft has not yet acknowledged these specific boot loops as "known issues" in official documentation, community forums and tech analysts report a significant volume of affected devices ^[2][9]. The practical impact ranges from minor annoyance to complete hardware downtime.

Symptom Category	Technical Identifiers	Practical Impact
Update Failure	0x800F0991, 0x80073712	The update fails to apply; the system may attempt to download it repeatedly [1].
Startup Failure	SENS Error, 0x800f0983	The PC is trapped in a boot loop, rendering the device unusable without recovery tools [7][9].
Connectivity	DHCP Error	The system loses internet access, preventing remote troubleshooting or further updates [1][9].

The errors appear to affect both Windows 11 24H2 and 25H2 versions ^[9]. Reports suggest that once the boot loop begins, traditional troubleshooting methods like adapter resets often fail to resolve the underlying corruption ^[1]. For many, the only reliable recovery method currently appears to be a repair reinstall or a manual rollback via Recovery Mode ^[1][9].

Root Causes / Analysis (Why Is This Happening?)

The technical issues surrounding the KB5077181 update appear to stem from a combination of confirmed software bugs and suspected hardware incompatibilities. While Microsoft has not officially categorized all reported symptoms as critical, several core triggers have been identified by technical analysts and affected users ^[1][5].

Confirmed Technical Factors

These issues have been verified through multiple user reports and technical documentation:

• Corrupted Installation Files: Many failures begin during the initial update process. Error codes such as 0x800F0991, 0x800F0983, and 0x80073712 typically indicate that the update package is missing components or has encountered file corruption during download ^[1][5].
• DHCP and Network Service Conflicts: A confirmed side effect for some users involves the breakdown of DHCP services. This causes a "connected but no internet" state where Wi-Fi remains active, but the system cannot assign an IP address to access the web ^[1][5][7].
• Credential Manager Failures: Reports indicate that the update can break the Windows Sign-in process, leading to login failures or specialized "Service Profile" errors that prevent users from reaching their desktops ^[5][7].

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Analysis of the Reboot Loop

The most severe symptom—the infinite reboot loop—is currently undergoing analysis. Experts have identified two primary likely causes:

1. Version-Specific Regression (24H2): Data suggests that devices running Windows 11 version 24H2 are disproportionately affected by boot loops ^[7]. This indicates a potential conflict between the new update's security patches and the core architecture of the 24H2 build.
2. GPU Configuration Conflicts: Evidence suggests that specific GPU configurations may trigger a Blue Screen of Death (BSOD) or restart cycle immediately after the patch is applied ^[8][9].

Trigger Type	Likely Impact	Status
24H2 OS Build	Infinite Reboot Loop	High Probability [7]
GPU Drivers	BSOD / System Instability	Confirmed by Sources [8][9]
Legacy Drivers	Printer & Peripheral Failure	Potential Risk [2]

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Hypotheses and Unverified Reports

Beyond the confirmed bugs, industry analysts are investigating several speculative causes:

• Secure Boot Changes: Some analysts suggest that a planned 2026 Secure Boot update may be interacting prematurely with current system firmware, potentially causing the "startup problems" reported by various outlets ^[2].
• WPA3 Wi-Fi Incompatibility: There are unverified indications that the update may break WPA3 encryption protocols on certain network cards, which could explain the widespread connectivity issues alongside the DHCP errors ^[8].
• Incomplete Rollback Loops: It is hypothesized that when the update fails (Error 0x800F0922), the Windows "Undo Changes" mechanism may fail to trigger correctly, trapping the PC in a loop where it attempts to install and uninstall the patch indefinitely ^[1][5].

Evidence & Reality Check

Reports from multiple technical outlets and user forums confirm that the February 2026 cumulative update for Windows 11, known as KB5077181, is causing significant stability issues ^[1][3]. While Microsoft has not yet categorized these as critical across all systems, the volume of documented installation failures and post-update bugs has placed update reliability under renewed scrutiny ^[3].

Data from community discussions and technical analysis highlights several recurring issues:

Issue Category	Common Error Codes / Symptoms	Reported Impact
Installation Failure	0x800F0991, 0x800F0983, 0x800F0922	Update fails to complete; rolls back [3][4]
Data Integrity	0x80073712	Missing or corrupted update files [3][4]
Connectivity	DHCP Errors	Wi-Fi connects but provides no internet access [3][4]
Security	CVE-2026-20841	Vulnerability in Notepad Markdown handling [1][16]

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Industry analysts and security researchers have identified specific catalysts for the current surge in troubleshooting traffic. The February 10, 2026, Patch Tuesday released fixes for 58 flaws, including six documented zero-day vulnerabilities that were actively exploited in the wild ^[16]. This high-pressure security environment often forces rapid deployment, which may contribute to the compatibility issues observed with KB5077181 ^[3][16].

Warning: Some users report that after the update fails with error 0x800F0983, it may later switch to error 0x800F0991 during subsequent attempts, even after running system repair tools ^[4].

Official documentation and independent reports suggest that the most severe symptoms, such as the inability to boot or total network failure, are currently affecting a subset of the user base rather than all devices ^[3]. However, the confirmed presence of "actively exploited" vulnerabilities means users must balance the risk of a buggy update against the risk of remaining unpatched ^[16]. Currently, the only verified "reliable" fix for persistent installation errors appears to be a repair reinstall of the operating system via the Windows Update recovery menu ^[4].

Self-Check / Diagnosis

Identifying whether your system instability is linked to the February update is essential before attempting a rollback. Use the following steps to verify if the KB5077181 update is the cause of your technical issues.

• Review your update history: Navigate to Settings > Windows Update > Update history. Check under the "Quality Updates" section to see if KB5077181 is listed as "Successfully installed" or "Failed to install" ^[1][6].
• Identify boot patterns: Observe if your computer enters an endless cycle of restarts immediately after an update attempt ^[5][6]. This "infinite boot loop" is a primary indicator of the botched patch ^[6].
• Check for specific error codes: If the update fails during the installation process, look for codes such as 0x800f0983, 0x800f0991, 0x800f0922, or 0x80073712 ^[1][5][6]. These are frequently reported in connection with this specific February release ^[1][6].
• Monitor the login screen: Look for a System Event Notification Service (SENS) error message when attempting to sign in ^[5][6]. This often indicates the system cannot interact with critical services due to missing data or network failures caused by the update ^[6].
• Verify network status: Check your Wi-Fi or Ethernet connection settings. If your status shows "Connected, no internet" or reports a DHCP error despite a functional router, the update may have disrupted your network adapters ^[1][6].

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If your device exhibits any of these symptoms, it is likely affected by the known issues with Windows 11 versions 24H2 and 25H2 following the February Patch Tuesday ^[5][6].

Symptom	Associated Error/Code	Impact Level
Installation Failure	0x800f0983, 0x800f0991	Moderate
Startup Loop	Infinite Restarts	Critical
Login Failure	SENS Error	High
No Internet	DHCP Error	Moderate

Warning: If you are currently in a boot loop, do not force-restart the machine repeatedly, as this can potentially lead to further file system corruption. ^[6]

Solutions / What to Do

If a system is experiencing boot loops or login failures following the February 2026 update, several documented methods may resolve the issue. Currently, there is no official fix from Microsoft, and the problems are not yet listed in the official "known issues" documentation for this patch ^[2].

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Standard Resolution: Uninstalling the Update

For users who can still access the desktop—even intermittently—the most direct solution is to manually remove the problematic update through the Windows interface.

1. Open Control Panel: Navigate to Programs and select Programs and Features.
2. View Updates: Click on View installed updates on the left-hand sidebar ^[2][25].
3. Locate Patch: Search for the update labeled KB5077181 ^[2][25].
4. Uninstall: Select the update and click Uninstall.
5. Restart: Follow the prompts to restart the computer to finalize the removal ^[25].

Important: After uninstalling, it is critical to navigate to Settings > Windows Update and select Pause Updates ^[2]. Failure to do this may cause Windows to automatically reinstall the faulty update, potentially triggering the boot loop again ^[2][25].

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Advanced Troubleshooting: Windows Recovery Environment

If the system is stuck in an endless restart cycle and cannot reach the login screen, users may need to utilize the Windows Recovery Environment (WinRE).

Reports suggest that entering recovery mode has had varying degrees of success depending on the specific error code encountered ^[2]. To attempt a manual removal via the command line, follow these steps:

• Access Recovery: Boot the PC into the recovery menu (typically by interrupting the boot process three times or using bootable media).
• Navigate to Tools: Select Troubleshoot > Advanced options > Command Prompt ^[25].
• Execute Command: Carefully type the following command and press Enter: wusa /uninstall /kb:5077181 /quiet /norestart ^[25].
• Exit: Close the command prompt and select Continue to boot back into Windows 11.

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Comparison of Recovery Methods

The following table summarizes the two primary ways to address the KB5077181 update issues:

Method	User Type	Requirement	Action
Control Panel	Beginner / Intermediate	Access to Desktop	Manual uninstall via GUI [2]
Command Prompt	Advanced	Recovery Environment	wusa command execution [25]
Update Pause	All Users	Post-Uninstall	Prevents automatic re-installation [2]

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Long-Term Prevention

Until Microsoft releases a verified fix or a replaced version of the February security patch, keeping updates paused is generally considered the most effective way to maintain system stability ^[2].

If technical errors like SENS, DHCP, or error codes 0x800f0983 and 0x800f0991 persist even after uninstallation, it may indicate underlying file corruption caused by the initial failed installation ^[2]. In such cases, some users have reportedly attempted system resets via recovery mode, though results remain inconsistent across different hardware configurations ^[2].

Risks, Limits, and When to Stop

Attempting to resolve update-related failures involves inherent risks to system stability and data accessibility. Cumulative updates like KB5077181 bundle multiple security fixes and feature adjustments ^[19]. When one element of this bundle fails, it can trigger an infinite reboot loop, making the operating system inaccessible ^[3][4][5].

The operational impact of these errors is significant, particularly for remote work environments. Beyond startup failures, verified reports indicate the update can cause DHCP errors, sign-in failures, and network loss ^[5][7]. Relying on automated rollback procedures may not always be successful, as recovery options often vary based on specific system configurations ^[19].

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When to Stop Troubleshooting

While some users may attempt manual repairs, there are clear indicators that a situation requires professional intervention or advanced recovery tools.

Scenario	Risk Level	Recommended Action
Recovery Environment Fails	High	Stop if the device cannot reach the Automatic Repair screen.
Manual Uninstall Errors	High	Stop if the "Uninstall Updates" tool returns an error code.
Persistent DHCP/Network Issues	Medium	Stop if standard netsh/ipconfig resets do not restore connectivity [5][7].
BitLocker Lockout	High	Stop if you do not have the BitLocker Recovery Key for the encrypted drive.

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Critical Warnings for Users

Warning: Manually forcing a shutdown during a "Undoing changes" loop can lead to permanent file system corruption or registry damage.

Users should be aware that recovery methods such as booting into Safe Mode or using recovery media are not guaranteed to work in every instance ^[19]. If the system does not stabilize after two manual uninstallation attempts, continued power-cycling may degrade the health of the storage drive.

Furthermore, while Microsoft may release a corrective patch or pause distribution if the issue is confirmed broadly, there is no set timeline for such a fix ^[19]. Experts suggest that organizations should generally stagger cumulative patches to avoid widespread disruption during these incidents ^[19].

FAQ

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What are the primary symptoms of the KB5077181 update failure?

The most critical issue reported by users is an infinite reboot loop, where the operating system fails to load and repeatedly restarts ^[3][4][5]. Additionally, some systems encounter install errors, DHCP connectivity issues, and sign-in failures ^[1][5][7]. There are also reports of Blue Screen of Death (BSOD) events occurring on specific GPU configurations and broken WPA3 Wi-Fi functionality ^[8].

Which versions of Windows 11 are most affected by these bugs?

Current data suggests that Windows 11 version 24H2 systems are particularly susceptible to boot loop issues and network loss ^[7]. While the February 2026 security update was deployed broadly, the most severe stability problems appear to be concentrated on these newer builds and certain hardware configurations ^[3][10].

Does KB5077181 provide any verified benefits or fixes?

Despite the reported bugs, the update was designed to resolve several high-priority issues. It addresses zero-day vulnerabilities, shutdown bugs, and Nvidia black screen errors ^[9][10]. It also includes performance optimizations for explorer.exe, the Taskbar, and the Start menu ^[9].

How can I address a device stuck in an infinite restart loop?

For devices already trapped in a reboot cycle, traditional troubleshooting often involves entering the Windows Recovery Environment (WinRE) to uninstall the latest quality update ^[3][4]. Microsoft has stated that a fix is rolling out for some related issues, such as WPA3 Wi-Fi disruptions and specific BSOD triggers, which may assist users who can still access their systems ^[8].

Are there reported issues with internet connectivity after this update?

Yes, multiple reports confirm that the update can cause DHCP errors and a total loss of network functionality on some 24H2 systems ^[5][7]. Furthermore, the update reportedly broke WPA3 Wi-Fi support for various users, though Microsoft has indicated that a resolution for this specific wireless issue is being deployed ^[8].

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Summary / Key Takeaways

• The KB5077181 security update for Windows 11 is causing critical system failures on some devices, most notably infinite reboot loops and "Blue Screen of Death" (BSOD) errors ^[3][4][8].
• While the patch was intended to resolve Nvidia black screen bugs and performance issues ^[9], it has introduced new stability problems involving DHCP errors, broken WPA3 Wi-Fi connectivity, and sign-in failures ^[5][8].
• Reports indicate that Windows 11 24H2 systems appear particularly susceptible to these boot loops and network loss issues ^[5][7].
• Microsoft has begun rolling out fixes for specific bugs, such as the GPU-related BSOD and Wi-Fi issues, but many users may still face installation errors or startup problems ^[1][8].

If you’re unsure, it’s usually cheaper to ask someone once than to fix a mistake later.

Quellen

^[1] Users report install errors and system bugs after Windows 11’s Feb update

^[2] February's Windows 11 update is causing startup problems for users

^[3] Windows 11 KB5077181 Security Update Causing Some Devices to Restart in an In...

^[4] Microsoft Windows 11 KB5077181 Update Triggers Infinite Restart Loop on Some ...

^[5] Windows 11 KB5077181: Update causes boot loops, DHCP errors, and sign-in fail...

^[6] Palo Alto Networks Firewall Vulnerability Allows an Attacker to Force Firewal...

^[7] Windows 11 KB5077181 boot loop issues on 24H2 systems fix for login failures ...

^[8] Microsoft says Windows 11 update causes BSOD on some GPU config, broke WPA3 W...

^[9] Windows 11 KB5077181 fixes gaming bugs, Nvidia black screen, and performance ...

^[10] Windows 11 February 2026 Patch: KB5077181 and KB5075941 fix zero-days, shutdo...

^[11] Windows 11 Update KB5077181 Traps Users in Boot Loops

^[12] How to Uninstall Windows Update (Windows 11 KB5077181)

^[13] Windows 11 KB5077181 boot loop fix: uninstall guide | tbreak

^[14] Windows 11 KB5077181 Update: What’s New, Critical Fixes, Known Issues & S...

^[15] KB5077181 - Details, Issues, & Feedback - NinjaOne

^[16] bleeping computer CVE-2026-20841 : Why Everyone’s Searching It — and How to T...

^[17] Reddit erupts over KB5077181: New update triggers rhythmic gaming stutter

^[18] Windows 11 Update KB5077181 Security and AI Features for 24H2 and 25H2 Versio...

^[19] Windows 11 KB5077181 Update Triggers Boot Loops

^[20] How to Find a BitLocker Recovery Key on Windows 10 & 11

^[21] My Windows 11 PC will refuse to start unless this USB drive is plugged in

^[22] What is BitLocker and is it safe? | Proton

^[23] Windows 11 Updates Are Underway Stuck - Here Is What You Need to Do!

^[24] Windows 11 KB5077181 targets Nvidia gaming bugs and explorer.exe crashes

^[25] Windows 11 users report issues after Feb. 2026 update. How to fix error

^[26] Windows 11 may finally let you move and resize the taskbar in 2026 as Microso...

^[27] How to check if Windows 11 has applied the new Secure Boot 2023 certificates ...

^[28] KB5077181 : corrections des écrans noir sur Windows 11 avec GPU NVIDIA - Over...

^[29] Windows 11 Update KB5077181 Triggers Infinite Restart Loop on Some Devices

^[30] Windows 11 Cumulative Updates KB5077181 & KB5075941 Released

^[31] XFN 1.1 profile

^[32] Windows Latest