Is there a metafile thumbnail viewer for Windows Vista and Windows 7?
In Windows Vista and Windows 7, when you display a folder in thumbnail view, it doesn’t display thumbnails of WMF and EMF files. I haven’t seen any official information about why this is. But my guess is they don’t want to risk triggering any security flaw in the metafile viewer code (see Microsoft Security Bulletin MS06-001: Vulnerability in Graphics Rendering Engine Could Allow Remote Code Execution for example). If you would like to try a free, third-party program to restore these thumbnails, check out the emfplugin for Windows Explorer.