This is correct. The problem seams on windows.
I was confused because I don't use MS Explorer, I use DOPUS and there the thumbnails where OK
They were also OK on SHAREX
But when I forced MS EXPLORER I found the same behavior.
Then I tried your recomendation.
Not all worked.
> e4uinit.exe -show
> taskkill /IM explorer.exe /F
> DEL /A /Q "%localappdata%\IconCache.db"
> DEL /A /F /Q "%localappdata%\Microsoft\Windows\Explorer\iconcache*" THIS COMMAND DID NOT WORK - SOME PRIVILEGE PROBLEM
> shutdown /r /f /t 00
But anyway the problem was solved after deleting IconCache.db and rebooting.
Thanks for the help