Chrome would not start. I spotted the problem down to the following situation:
The following folder
C:\Users\User\AppData\Local\Google\Chrome\User Data
is locked - always. Also when chrome is not running. Also immediately after a reboot.
Furthermore, I tried to unlock it with both the "unlocker" and "lockhunter" applications. Both applications claim that the folder is not locked, however, when asking them to rename it they fail.