disk I/O error

@oksma: Note, though, that you're getting disk I/O errors in Zotero, which would cause all sorts of things to fail. This is a generic disk error, so we can't tell you specifically what the problem is, but the most common cause is having your Zotero data directory on a network filesystem or in a cloud storage folder (where it should never be). It could also be due to an actual physical problem with your disk or due to security software interfering with Zotero's ability to access the disk.