[Phil Reinemann]

Originally Posted by Graham Mayor

Frankly I don't know why the Office clipboard is in any way involved if you
are copying via the operating system.

Graham Mayor - Word MVP

I was having the same "format not supported by Office Clipboard" too when I tried to copy two files from one directory to another directory (one on the local drive the other on a network drive). (Win7 Pro, Office 2007.)

Part of the function of the Office Clipboard is that if you have an Office app open the Office Clipboard is open too, so you have two choices (maybe more, I only looked at two):
1) Exit all Office apps (Word, Excel, Outlook(?), Access, PowerPoint, etc).
2) Probably simpler, right-click on the Office Clipboard in the taskbar and select Stop Collecting.

Once you're done what you need, if an Office app is still open, activate that window and the Office Clipboard should again start collecting. If you've already closed all Office apps the Office Clipboard will reopen when you reopen an Office app.

It's odd, because it doesn't seem to always work this way. (I didn't try minimizing the Office app, but that may work too.)