Windows 10 / windows 11 : Lenteur du démarrage

Hi Bruno, I'm Henry. I’d like to share some thoughts on your issue. While I’m unable to reply in your native language, I’ve translated the content to better understand your situation.

A specific update, the 2025-09 Cumulative Update for Windows 11 Version 24H2 (KB5065426), has been identified by users in Microsoft forum as a potential cause for significant slowdowns in startup times. One user reported that uninstalling this update resolved the issue and returned their computer to its previous speed. Similarly, a Windows 10 update from early September 2025, KB5065429, has also been associated with high CPU usage after installation, which could contribute to slower boot times.

Given that the problem persists on different networks, it is likely related to a recent software change on the computers, such as a Windows update, rather than a network-specific issue.

My Recommendation is Uninstall the Latest Cumulative Update. The most step to troubleshoot this issue is to uninstall the latest cumulative update.

If you are unable to uninstall the update through the Settings menu, you can use the Command Prompt:

1. Open Command Prompt as an administrator.
2. To see a list of installed updates, type the following command and press Enter: wmic qfe list brief /format:table
3. To uninstall a specific update, use the following command, replacing "KBNUMBER" with the actual KB number of the update you wish to remove: wusa /uninstall /kb:KBNUMBER
4. Confirm the action when prompted and restart your computer.

If uninstalling the recent update does not resolve the slow startup times, here are some other general troubleshooting steps that can help:

• Disable Fast Startup: This feature can sometimes cause boot issues. You can disable it in Power Options > Choose what the power buttons do > Change settings that are currently unavailable.
• Manage Startup Programs: Too many applications launching at startup can significantly slow down the process. You can manage these in the Startup tab of the Task Manager (Ctrl + Shift + Esc).
• Update Graphics Drivers: Outdated or incompatible graphics drivers have been known to cause slow boot times after a Windows update.
• Run System File Checker: Corrupted system files can lead to performance issues. You can run the System File Checker by opening Command Prompt as an administrator and typing sfc /scannow.

I hope this information and these keywords help point you in the right direction for your research. Let me know how it goes, and if this answer helps, feel free to hit “Accept Answer” so others can benefit too

Bonjour et merci @Henry Mai pour votre retour.

La désinstallation de cette mise à jour n'est pas possible en mode "adminstrateur" via le command prompt :

:(
Je cherche une autre solution
merci encore ;)