Windows XP automatically generate thumbnail preview for images, pictures, photos, videos, HTML pages and other media clips with format supported by the operating system. The image or media preview is shown in the Details pane on the left of Windows Explorer, or when the files are viewed in Thumbnails view.

However, some users may not want or prefer the automatic preview and thumbnail generation when browsing files list. The preview hide the icon of the files, and doesn’t allow users to instantly know the format or extension of the files, such as whether a video is of .avi, .wmv or .mpg format. Beside, the process to show the thumbnail preview may slow down the file listing process when opening folder with video files. Beside, the preview on no codec or corrupted movie or video clip (i.e. no index from a partial download) may cause system problems such as Windows XP stops responding or freezing with 100% CPU utilization, and prevent users from deleting, renaming or moving the file until the file is completely loaded. The error happens because Windows needs a proper codec in order to correctly and validly create a thumbnail for video media. Without codec, or codec is broken or buggy will have problem.

To turn off, remove or disable video and media thumbnail preview in Windows XP, and fix above issues relating to video (AVI) problems, simply issue the following command in a Command Prompt window. To open Command Prompt window, type “Cmd” in Start -> Run box.

regsvr32 /u shmedia.dll

It’s important to note that once the command above is run, the thumbnail preview will be disabled and will not be shown or displayed for all video, movie and other media files. And, users also lose the ability to see the summary properties in the tooltip and file properties dialog for AVI, WMA, WMV, ASF and WAV files.

To re-enable, or turn off the media preview again, use the following command:

regsvr32 shmedia.dll

There is another trick to disable and turn off preview thumbnail generation for image and photos, which use Windows Picture and Fax Viewer.