Explorer deosn't do a folder task

[Guest]

When we explorer a folder in "thumbnail" mode, in it, if there is some
folders with
pictures, the folder icon change, become bigger, and 4 previews appear in
this icon.
We can choose a picture in this icon (right
click/proprieties/customize/chose a picture)

This functions doesn't work :-(

I access this folder with a second computer.
This functions work.
Changes don't affect the first computer which has these folders.

1) It's not a corrupted folder or file in there folder.
2) Seem an explorer task doesn't work.
3) May be the emplacement where folder data (for customize) is broken.

I tried :
_ reinstall shimgvw.dll
_ delete cache folders
[-HKEY_CURRENT_USER\Software\Microsoft\Windows\ShellNoRoam\BagMRU]
[-HKEY_CURRENT_USER\Software\Microsoft\Windows\ShellNoRoam\Bags]

 

[Guest]

After 2 months ! Ouch !
Tank you all for yours ideas
By eliminate, I arrive here with you.

It was 2 registry key :

HKCR\Directory\shellex\{BB2E617C-0920-11d1-9A0B-00C04FC2D6C1}
value:{9FA2564D-A9DD-4330-94FF-EC75ADE0798A}

HKCR\Folder\shellex\{BB2E617C-0920-11d1-9A0B-00C04FC2D6C1}
value:{9FA2564D-A9DD-4330-94FF-EC75ADE0798A}

Its may be arrive with a software install.
Come from DLL
C:\WINDOWS\System32\AcShlExt.dll
ArCon Folder Thumview (O2C)
UP-Vision Computergraphik GmbH
http://www.o2c.de