We have seen some issues with thumbnail previews not displaying in Windows Explorer. On some machines, the Revit family and project file thumbnail previews don’t show up.
In most case, it is related to a specific dll file. For Revit 2012, it is Revit.Thumbnail.dll, and for Revit 2011 and 2010 version, it is Revit.FilePreview.dll.
In order to fix this, follow the steps below:
Click Start- -Run
Enter regsvr32 /u "C:\Program Files\Autodesk\Revit Architecture 2012\Program\Revit.Thumbnail.dll"
Click OK, a message will show up saying DllUnregisterServer succeeded, click OK.
Click Start- -Run
Enter regsvr32 "C:\Program Files\Autodesk\Revit Architecture 2012\Program\Revit.Thumbnail.dll"
Click OK, a message will show up saying DllRegisterServer succeeded.
Note:
You need to modify the path above based on your own Revit installation folder. If you can’t find this dll file on your machine, you can copy it from DVD or other machine.
For Revit 2011 and 2010, replace Revit.Thumbnail.dll with Revit.FilePreview.dll in the path above.