I am having this same issue on a Mac, just as of last month. I found this thread today since this is the second time the issue has arisen. The first time, I found nothing online to help. I tried uninstall, restart, install, to no avail. Then, I also deleted my sqlite along with ALL Zotero support files I could find. Then reinstalled and just logged in and downloaded everything from the cloud again (Zotero cloud, Zotero sync). So I know I can probably solve the problem again but this is a major headache for me. Do you know the cause of this? Is it something I can avoid? My company has some security software on my computer but I do not have issues like this with any other software so I doubt that is the issue. Thanks for any insight: faster fix, known issues to avoid, or schedule for the long-term solution from Zotero?

@mattkrebs: Please always start new threads for new issues. I've moved this to a new thread. You'll need to explain here, in your own words, what the exact problem is you're facing. But you certainly didn't need to delete your Zotero data, and we strongly discourage taking those sort of drastic actions without just asking us for help.

https://www.zotero.org/support/reporting_problems