Sub-collections vanish with syncing

GeorgGraeser · 2026-03-01T20:03:24+00:00

After collecting about 200 titles in zotero I registered and tried to sync. With syncing most (not all) of my sub-collections vanish. The items are still there, but doubled in the top "my library" -say: if I had an item in three sub-collections, I have now three identical items in the top-Library. I restored the sub-libraries by hand, synced again and the sub-collections are gone again! They are not in the waste-bucket either. How can I keep my sub-collections and why are some vanishing, others not? Seems a serious buck to me. Any suggestions anybody?

dstillman · 2026-03-01T20:06:19+00:00

Syncing doesn't delete things you didn't delete yourself and doesn't duplicate items.

No collections in your library have ever been permanently deleted, but you have lots of collections in the trash. You can restore them from there.

If you're seeing duplicate items, you likely did an export/import on another computer, and now you're seeing both the original and imported items. Sort the the items list by Date Added and you should be able to delete the entire set of imported items.

GeorgGraeser · 2026-03-02T08:08:41+00:00

Thanks for your help! - Yes, I tried first to export-import, on a second pc and then even changed something there, although it should only figure as an backup - later I thought: "syncing is easier", so I configured syncing. Now both seems confused.

Not as simple as I thought - it seems important not to mix up syncing AND Import-Export. I am learning... thanks!