Currently no references are showing up at all in my Zotero library. So far I have tried:
* Checking for incompatible extensions (happy to list the ones I have installed if that helps)
* Checking Z was using the correct data directory (I am using a custom directory, but switching to the default one and restarting did not restore my data)
* Restoring from the sqlite backup
(as outlined here http://www.zotero.org/support/zotero_data )

None of the above worked. I do back up my hard drive regularly, but I have not yet tried to restore from an external backup for two reasons: first, I backed up recently and don't know if what I backed up was an empty zotero library - restoring it might therefore not be a good idea. Second, my custom zotero directory is about 400MB, and the storage directory is full of pdfs and folders suggesting my data is all still there - it's just that Zotero isn't seeing it.

I also have a (synced) online account which is (still) reporting that I'm at the limit for free storage, despite my seeing no entries in my library.

Now a confession: I think the problem originally came about because I installed zotero on a work computer and synced my data to it to use. Because it's a shared computer I then deleted everything from the library and turned sync off. I can only assume in the short while between these things happening a sync took place.

Any suggestions gratefully received...