Why does SU think the file is open?

[DanRathbun]

With regard to the “ThumbsUp.dll” … you could try a simple test, by renaming it, and reboot (since this is an Explorer bug,) and restart SketchUp. Then retry…

This was suggested by SketchUp Team member Jody here:

Files open as read-only

We’re currently investigating this issue. Some users report that trying a second time and the file will open without the message so you might just be able to persevere to get it working. Another possible culprit is the Preview Pane in Windows Explorer. Try disabling that and see if the error continues. Finally, as @thomthom mentioned, this may be tied to the thumbnails and the workaround to rename the “thumbsup.dll” file to “thumbsup.old” may work as well. Be sure to let us know in this threa…

If this does not work you could try one of the 32-bit editions.