Error message "Cannot find central directory" when trying to add file to project

I use SDL Trados Studio 2014 Freelance on a Macbook Air via Parallels.

I recently copied my files onto iCloud Drive due to lack of space. I got an error message saying I had too many files to do this, but the files were transferred to iCloud Drive anyway, however no copies were left on my Mac. I subsequently installed a larger hard disk and used a Time Machine backup to recover my files.

I'm now having constant problems using Studio. The latest one is the above.

Any help much appreciated.

Andy