Q: Aperture - I currently have 365 projects. When I try and add one now nothing happens. It just highlights one of my existing projects. The same thing happens when I try and add a folder. What is wrong?

Have you checked the search field in the library inspector panel? If this is not set to "All Items" the source list will be filtered, and you may not be able to see your new projects, if the do not match the filter.

Regards

Léonie

Have you repaired or rebuilt your Library?  That's the next step.  Back up first (but I have never had a bad experience with either).  If your Library is large (c. >250 GB) let it run overnight.  Let us know if this helps.

If it doesn't, remove your User Preferences.  Directions are on the same Apple page.

As a start what happens if you create a new empty library and attempt to make a project in that?

If that still does not work make a new user, log in as that user and run Aperture on a new empty library. Can you make a project here?

Post the results back.