Windows 11 KB5072033: December 2025 Update Slowdown Issues

What This Article Covers

• The Root Cause: How the AppX Deployment Service (AppXSVC) change is affecting system resources.
• Symptoms: High CPU, RAM, and disk usage at startup.
• The "Delivery Optimization" Factor: Another service contributing to the lag.
• Current Fixes: How to regain performance while waiting for an official patch.

Core Explanation

The primary cause of the slowdown is a change in the AppX Deployment Service (AppXSVC) behavior. Previously, this service—which handles Microsoft Store app installations and updates—was set to "Manual (Trigger Start)," meaning it only ran when needed.

With update KB5072033, Microsoft has switched this service to "Automatic." Consequently, the service now launches immediately upon system boot and stays active in the background. For many users, especially those on lower-end hardware or systems with limited RAM, this results in:

• High CPU Spikes: As the service scans for app updates during the boot sequence.
• Memory Leaks: Reports suggest the service can sometimes consume several gigabytes of RAM unnecessarily.
• Disk Usage: Continuous background indexing of app packages.

Additionally, some users have reported that the Delivery Optimization service is also spiking in memory usage (in some extreme cases up to 20GB) following this update.

Practical Workarounds

Since Microsoft has not yet released a "revert" patch, users are currently using the following methods to restore speed:

1. Disable "Allow downloads from other PCs"

This helps if Delivery Optimization is the cause of your RAM drain:

• Go to Settings > Windows Update > Advanced Options.
• Select Delivery Optimization.
• Toggle "Allow downloads from other PCs" to Off.

2. Reset the AppX Package via PowerShell

If the Store service is stuck in a loop:

• Right-click the Start button and select Terminal (Admin) or PowerShell (Admin).
• Run the following command to reset the Security Health component (often linked to these loops): Get-AppxPackage Microsoft.SecHealthUI -AllUsers | Reset-AppxPackage

3. Uninstall the Update (Last Resort)

If the system is unusable, you can roll back the update:

• Go to Settings > Windows Update > Update History.
• Scroll to the bottom and click Uninstall updates.
• Locate KB5072033 and click Uninstall.
• Note: This will remove recent security patches, so only do this if performance is critical.

Common Mistakes and Misunderstandings

• "My SSD is dying": Many users mistake the sudden disk usage for a hardware failure. If the slowness started exactly after the December update, it is almost certainly a software issue.
• "Manually disabling AppXSVC": While tempting, setting AppXSVC to "Disabled" in Services.msc can break the Microsoft Store, Windows Photos, and even the Calculator. It is better to wait for an official fix than to permanently break system apps.

Limitations and Trade-Offs

• Security vs. Speed: KB5072033 includes critical fixes for remote code execution vulnerabilities. Uninstalling it leaves your system "open" to these specific threats.
• Official Recommendation: Microsoft acknowledges the startup change but warns that the service is "Automatic" to improve stability in specific scenarios. They currently do not recommend manual registry edits to change it back to Manual.

Summary and Final Thoughts

The Windows 11 December 2025 update is a classic example of a security "fix" creating a usability "break." By forcing the AppX Deployment Service to run at startup, Microsoft inadvertently hindered performance for millions of users. Until a follow-up "Cumulative Update Preview" is released (likely in early January 2026), toggling off Delivery Optimization is the safest way to maintain performance.