Microsoft's September 2023 update for Windows 11 (KB5043145) has been causing unexpected performance issues and glitches for many users. The update, which was intended to deliver security improvements and minor feature enhancements, has instead resulted in widespread reports of system slowdowns, application crashes, and other stability problems.

The Scope of the Problems

Since the release of KB5043145 on September 12, 2023, user forums and support channels have been flooded with complaints about:

  • System slowdowns: Many users report significantly reduced performance, especially during multitasking
  • Application crashes: Frequent crashes in Microsoft Edge, Office apps, and even File Explorer
  • Boot time increases: Some systems take 2-3 times longer to start up after the update
  • Wi-Fi connectivity issues: Intermittent drops in wireless network connections
  • Audio glitches: Crackling or distorted sound output on some systems

Microsoft's Response

Microsoft has acknowledged some of these issues in a support document updated on September 18. The company states:

"We're aware of reports that some users are experiencing performance issues after installing KB5043145. Our engineers are actively investigating these reports."

However, as of this writing, no official fix or workaround has been provided beyond the standard troubleshooting steps:

  1. Running the Windows Update Troubleshooter
  2. Performing a clean boot to identify conflicting software
  3. Resetting Windows Update components
  4. Considering a system restore to the pre-update state

Technical Analysis

Early analysis by Windows experts suggests several potential causes:

  • Memory management changes: The update appears to have modified how Windows handles memory allocation
  • Driver compatibility issues: Some hardware drivers aren't properly initializing after the update
  • Background process conflicts: New security processes may be consuming more resources than intended

User Workarounds

While waiting for an official fix, some users have reported success with these unofficial solutions:

  • Disabling Windows Defender Real-Time Protection temporarily
  • Rolling back specific drivers (especially for audio and networking)
  • Adjusting virtual memory settings to compensate for memory management changes
  • Using DISM and SFC commands to repair system files:
    dism /online /cleanup-image /restorehealth sfc /scannow

Enterprise Impact

The problems appear to be affecting both home and enterprise users, though organizations using Windows Update for Business have more options to delay or block problematic updates. IT administrators report:

  • Increased help desk tickets related to update issues
  • Productivity losses from affected workstations
  • Concerns about deploying the update to critical systems

Historical Context

This isn't the first time a Windows update has caused widespread issues. Similar problems occurred with:

  • The October 2018 Update (version 1809) that deleted user files
  • The January 2022 Update that broke VPN connections
  • The February 2023 Update that caused blue screens on some systems

What Users Should Do Now

For most users, the recommended course of action is:

  1. Back up important data if you haven't already
  2. Consider pausing updates if you haven't installed KB5043145 yet
  3. Monitor official channels for Microsoft's response
  4. Report issues through the Feedback Hub to help Microsoft diagnose problems

Looking Ahead

Microsoft typically releases out-of-band updates for serious issues within 2-3 weeks. Users experiencing severe problems may need to:

  • Uninstall the update through Settings > Windows Update > Update History
  • Use the Media Creation Tool to perform an in-place upgrade
  • Wait for the next Patch Tuesday (October 10) for a potential fix

As always with Windows updates, the situation remains fluid, and we'll continue to monitor developments.