Thumbnails

Codec Tweak Tool > Thumbnails

How do I disable thumbnail generation for a specific file extension?

You can enable and disable thumbnails very easily with the Codec Tweak Tool.

If you want to do it manually, then follow the instructions below.

1. Start the Windows Registry Editor program:
   WinKey+R -> regedit.exe
2. Navigate to the following key:
   HKEY_CLASSES_ROOT\.xyz\ShellEx\{BB2E617C-0920-11d1-9A0B-00C04FC2D6C1}
   (replace .xyz with the desired file extension)
3. Right-click on {BB2E617C-0920-11d1-9A0B-00C04FC2D6C1} and select Delete.
4. Do this same for this key if it exists:
   HKEY_CLASSES_ROOT\.xyz\ShellEx\{e357fccd-a995-4576-b01f-234630154e96}

Execute the following command to enable the Explorer shell extension that is responsible for thumbnail generation:

Start -> Run -> regsvr32 shmedia.dll

That can usually be soved by clearing the thumbnail cache.

Windows Vista/7/8:

1. Run the Windows Disk Cleanup tool:
   Start -> All Programs -> Accessories -> System Tools -> Disk Cleanup
   or
   WinKey+R -> cleanmgr.exe
2. Choose C: and press OK.
3. Enable the checkbox for Thumbnails and press OK.

Windows XP:

On Windows XP the thumbnail cache is not stored in a central location, but stored in a hidden file called Thumbs.db in each individual folder that contains videos and images.

1. From Windows Explorer, click the Tools menu, then select Folder Options.
2. Click on the View tab.
3. Make sure Show hidden files and folders is selected.
4. Uncheck Hide protected files and folders.
5. Uncheck Hide protected operating files. Click OK when the warning appears.
6. Click OK to close the Folder Options dialog box.

Now you should be able to see the Thumbs.db file in each folder. Delete it to clear the thumbnail cache for that folder. To quickly delete all such files from your computer, you can use the search function of Windows.

Known causes:

1. The video has an unusual aspect ratio.
2. You enabled the option in the codec pack to hide it.
3. A Registry key is missing that identifies the file extension as a video format. The relevant key is:
   HKEY_CLASSES_ROOT\.extension, value: "PerceivedType" = "video"
4. Explorer has been configured to hide it. This is the relevant Registry key:
   HKEY_CLASSES_ROOT\SystemFileAssociations\video, value "Treatment"
   0 = disabled, 3 = enabled