Windows – How to enable thumbnail previews for the non-standard (mp4 avi mov mkv) video files in Windows 8

When you install K-Lite Codec Pack, towards the end of the installer, it asks you if you want to have thumbnails generated for all the file types it supports. You get thumbnails for quite a lot of formats, including, I believe, for mov files.

1. Disabling thumbnails for all video types

• Disable: regsvr32 /u shmedia.dll
• Enable: regsvr32 shmedia.dll

(source 1, source 2)

2. Disabling thumbnails for all image types

• Disable: regsvr32.exe /u shimgvw.dll
• Enable: regsvr32.exe shimgvw.dll

Alternately, you can disable them in RegEdit by clearing (ie, setting the value to blank, empty space) the "(Default)" value on the following key:

HKEY_CLASSES_ROOT\SystemFileAssociations\image\ShellEx\ContextMenuHandlers\ShellImagePreview

For easy restoration, backup (export) the key first, then merge your backup into the registry; or set the value back to its default of "{e84fda7c-1d6a-45f6-b725-cb260c236066}".

(source)

3a. Disabling thumbnails for individual video types

The K-Lite Codec Tweak Tool will conveniently accomplish this. It works by backing up and deleting the following registry key (where .xxx is a file extension):

HKEY_CLASSES_ROOT\.xxx\ShellEx\{BB2E617C-0920-11d1-9A0B-00C04FC2D6C1}

Manually removing this key with RegEdit also works; again, export the key first to be able to restore it.

3b. Disabling thumbnails for individual image types

I've tried (in a virtual machine!) deleting all registry keys featuring the string "jpg", to no avail. I don't think it's feasible, short of hex-editing some system DLL.