"Unspecified error" when drag and drop PDFs in new version
I preferred the previous versions of Zotero. One of the reasons is that one could drag and drop selected PDFs into a folder of the Windows Explorer. Now there is an "unspecified error" and one needs to right-click > Show File and copy/paste the PDFs one by one.
Upgrade Storage
https://forums.zotero.org/discussion/comment/518008/#Comment_518008
You should figure out why you're not receiving automatic updates.