Miniaturansichten anzeigen im Ordner

Hi @Joachim262923654c5n 

Sorry for the delay in response. 

Please try the exact steps as suggested here: https://helpx.adobe.com/acrobat/using/enable-pdf-thumbnail-preview-windows-explorer.html 

If this isn't successful, then please check the following:

Go to Acrobat Reader> Help > Check for updates and reboot the computer once (you must save all the work before restarting)

To download the patch manually, more information about this release is here: Release Notes | Adobe Acrobat, Reader 

Once done, please reboot your system and try again. 

Thanks,

Akanchha