One of my collections has disappeared and I can't find it anywhere. I don't seem to have moved it into any other collection and my bin is empty. I also can't undo any actions.
You can likely restore it from the last automatic backup. Note the specific instruction for restoring collections.
You should also upgrade to Zotero 7 via Help → Check for Updates if you're still on Zotero 6. Zotero 7 sends deleted collections to the trash rather than deleting them immediately.
Upgrade Storage
You can likely restore it from the last automatic backup. Note the specific instruction for restoring collections.
You should also upgrade to Zotero 7 via Help → Check for Updates if you're still on Zotero 6. Zotero 7 sends deleted collections to the trash rather than deleting them immediately.