Aperture 3 thinks all of my referenced TIFFs are audio/video.

All of the TIFFs in my referenced libraries have, quite abruptly, stopped being recognized as images. This means I cannot edit them and cannot export versions.

Choosing "consolidate originals" to bring them back into the local library does not rectify the problem. If I "export original" and re-import it does solve the issue.

There are no problems with TIFFs in my managed (i.e. local) library.

Anyone have a clue what might be causing this?

Thank you.

MacBook Pro with retina display (mid 2012)

Aperture 3.4.5

Mac OS X 10.8.4