Solved sihost.exe prevents most programs to start since June 7, 2024

Hi,

since yesterday, I can hardly open any program after Windows 11 starts. Firefox reports it's already running (which it is not), OneNote produces another error message, a screenshot tool (Faststone) opens, but does not allow me to save the screenshot anywhere, claiming it does not have sufficient rights.

By killing process after process, I identified sihost.exe as culprit. When I kill it, it restarts and almost everything is working as normal (some symbols in the "hidden taskbar" are missing).

Yesterday, I restored the last Windows recovery point which fixed the problem until after 2-3 restarts today. Then, the problem reappeared, although not immediately after the windows update KB5037771, which was also installed today (not sure if it was also installed yesterday before the restore). The sihost.exe version is the following:




My system version: Windows 11, Version 23H2 (Build 22631.3593)

Has anybody observed something similar or have any idea what could be going on and how to solve this?

Thanks a lot for any help!

Maybe these pages have some help:

Killing process after process is not the way to troubleshoot and actually doesn't prove anything definitive. Things to try:

1. If you have any third party app that alters the GUI, uninstall it.

2. Scan for malware. Use Malwarebytes free to scan for Malware. Free Antivirus 2024 | Download Free Antivirus & Virus Scan | 100% Free & Easy Install

3. Perform a clean boot to eliminate software conflict causing the issue. If it doesn't happen in a clean boot, you have some software conflicting with Windows. Brink's procedure will help you weed out which one. Perform a Clean Boot in Windows 11 to Troubleshoot Software Conflicts Tutorial

4. Make sure you have no corrupt system files that is causing this problem. Open a command prompt as administrator and type sfc /scannow
Pay attention to the scan results to see if SFC found anything it could not repair. If it found corruption it could not fix followup with this command (note the spaces)
dism /online /cleanup-image /restorehealth
Restart computer

5. Repair install Windows 11 with an inplace upgrade Repair Install Windows 11 with an In-place Upgrade Tutorial

Thanks, I'll give that a try. For now, I did a restore to before the Windows update, and the problems are gone again. But I am sure they'll return, soon.

The issue returned like 1 hour later, even without any windows update

But the clean boot approach did the trick! The following service was the culprit: SmartNoteService by Lenovo

Thanks a lot for your help!! Is there any way of tagging your answer as solution?