CRITICAL_PROCESS_DIED error after updating Windows 11
Yesterday, I was confronted with a very strange issue. Someone brought me a computer with Windows 11 that would not boot any longer, not even in safe mode. Any attempt to boot the system would fail with a “CRITICAL_PROCESS_DIED” bluescreen. The last thing that they had done was installing the latest Windows updates. They had already (unsuccessfully) attempted to restore the system from the restore point before the installing the updates.
My first suspicion, was a hardware problem unrelated to the Windows updates, but this suspicion could not be confirmed. I again tried to restore the restore point, but this was not possible because the tool reported the following problem:
You must enable system protection on this drive.
Or in the German language variant of Windows:
Sie müssen für dieses Laufwerk den Computerschutz aktivieren.
Spoiler: System protection actually was activated.
So, I suspected that some system files might be corrupted and tried to repair the system using sfc and dism, but an online repair would not work because in Windows RE, such a repair would try to repair Windows RE instead of the installed system, and attempts to run an offline repair failed as well (with error messages that were not very enlightening).
After doing some research, I found that the problem with restoring the restore point might be circumvented by directly running rstrui /offline:C:\Windows=active. Now, the UI would allow me to actually start the restore, but the restore operation would fail with the following error message:
System Restore failed while restoring the registry from the restore point. An unspecified error occurred during System Restore. (0x80070002)
Or in the German language variant of Windows:
Systemwieederherstellungsfehler beim Wiederherstellen der Registrierung aus dem Wiederherstellungspunkt. Unbekannter Fehler bei der Systemwiederherstellung. (0x80070002).
This would happen regardless of whether I was trying to restore the most recent or an older restore point.
Luckily, I found the solution to this problem in the Dell support forum: I had to rename the two system registry files:
cd C:\Windows\System32\config
ren SOFTWARE SOFTWARE.001
ren SYSTEM SYSTEM.001
After that, I again ran rstrui, and this time the system restore succeeded and Windows would start again.
After booting into the Windows system, I again ran dism and sfc, this time using online repair. These repair operations succeeded and while dism did not find any issues, sfc found that one driver file (bthmodem.sys) was currupted.
Finally, I deleted the SOFTWARE.001 and SYSTEM.001 files and again installed the Windows update that was reverted by restoring the restore point. I do not know what went wrong when the update was installed the first time, but this time the update could be installed without making the problem appear again.