When opening a single number or letter named folder, explorer.exe's digital signature is wrong and cannot be opened.
Generally speaking, it is caused by a virus. You can try this, press F8 on the boot system menu to enter safe mode, and then do the same operation and test again. If it is normal, it is caused by a virus or a recently installed plug-in, only anti-virus can be considered. If you can't kill, you can conduct a comprehensive killing test in safe mode. If the mistakes still exist, there is something wrong with explorer.exe. You can try to repair the registry. Invalid download a explorer.exe, and then replace the original with winPE.