Microsoft's latest Windows 11 update, KB5051987, has introduced several performance improvements and security patches, but some users are reporting significant File Explorer issues. This cumulative update, released as part of the March 2024 Patch Tuesday, aims to enhance system stability while addressing critical vulnerabilities. However, the unintended side effects have created frustration for many users navigating their file systems.

What KB5051987 Changes

The KB5051987 update includes:
- Security updates for Windows Kernel and Microsoft Defender
- Performance improvements for hybrid CPU architectures
- Fixes for memory leaks in certain system processes
- Updated daylight saving time rules

Microsoft's official changelog states the update "addresses security issues for your Windows operating system," but makes no mention of File Explorer modifications.

Reported File Explorer Issues

Users across Microsoft forums and tech communities report these problems after installing KB5051987:

1. Slow Performance and Freezing

Many users experience:
- 3-5 second delays when opening folders
- Complete freezes when accessing network locations
- High CPU usage by explorer.exe (often 20-30%)

2. Context Menu Problems

Right-click functionality appears broken for some:
- Menu takes 8-10 seconds to appear
- Some third-party context menu items missing
- Occasional crashes when accessing properties

3. Search Functionality Degradation

File Explorer search exhibits:
- Incomplete results for recent files
- Failure to index new network locations
- Crashes when searching large directories

4. Thumbnail Display Issues

Graphic professionals report:
- Missing previews for RAW image files
- Incorrect thumbnails for video files
- Blank icons for certain document types

Microsoft's Response

While Microsoft hasn't officially acknowledged these issues, support agents on the Microsoft Answers forum have suggested:

  1. Basic Troubleshooting Steps
    - Restart File Explorer through Task Manager
    - Run the Windows Search and Indexer troubleshooter
    - Clear the thumbnail cache

  2. System File Checker Scan
    Open Command Prompt as Administrator and run:

sfc /scannow
  1. DISM Repair
    For more serious corruption:
DISM /Online /Cleanup-Image /RestoreHealth

Effective Workarounds

Based on user testing, these solutions show the most success:

1. Disable Enhanced Search Mode

  1. Open Indexing Options
  2. Click Advanced
  3. Select "Troubleshoot search and indexing"
  4. Choose "Rebuild index"

2. Modify Explorer Patches

Create this registry key (backup first):

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Shell Extensions\Blocked

Add string values for problematic shell extensions.

3. Network Drive Optimization

For network-related issues:
1. Map drives using IP instead of hostname
2. Disable automatic reconnection at sign-in
3. Adjust SMB protocol version in Windows Features

4. Clean Boot State

  1. Open System Configuration (msconfig)
  2. Select "Selective startup"
  3. Disable all startup items
  4. Restart and test File Explorer

Should You Uninstall KB5051987?

For users severely impacted:
1. Open Settings > Windows Update > Update History
2. Click "Uninstall updates"
3. Locate KB5051987 and select Uninstall

Note: This removes security patches, so only use as last resort.

Long-Term Solutions

Microsoft will likely address these issues in one of two ways:

  1. Out-of-Band Update: A special patch released between monthly updates
  2. April 2024 Cumulative Update: Fixes bundled with next Patch Tuesday

Users can monitor the Windows Health Dashboard for official updates.

Preventing Future Update Issues

  1. Enable update delay in Windows Update settings
  2. Create system restore points before installing updates
  3. Monitor tech forums before applying patches
  4. Consider using the Windows Insider program for early issue detection

While KB5051987's File Explorer issues are frustrating, they appear to affect a minority of users. Most systems continue operating normally with the enhanced security protections this update provides.