Two (sub)collections suddenly disappeared. Trying to save them from Zotero.sqlite.bak files

Gulbin

Just an hour ago, when I was dropping new pdf files into zotero collections, suddenly two subcollections disappeared. I do not know how that happened. I have been trying to bring these collections back and I have come across this information:

"Look for larger zotero.sqlite.bak files in the data directory, or look for a larger zotero.sqlite file in any separate backups you have. (It's not possible to restore your data from the 'storage' files alone.) When Zotero starts up, it reads the zotero.sqlite file in the active data directory, so you can try other copies of zotero.sqlite by copying them to that location and filename. Do not try to import an .sqlite file into Zotero via File → “Import…” — it won't work."

In my data directory, I have found 3 zotero.sqlite.bak files, two of them pretty recent: one from 25 November 2022 (123,4 MB) and one from today (124 MB). However, I am totally inexperienced in these things and having hard time figuring out what to do next. I am using macOS. Could you please help me?

dstillman

First, you should make backups of the two .bak files in another folder.

Beyond that, there's not much more we can say beyond what it says there. If there's something specific you don't understand, you should explain what you're confused by, but we can't provide general Mac usage guidance.

Gulbin

Hi, I have managed to get the collections back. "When Zotero starts up, it reads the zotero.sqlite file in the active data directory, so you can try other copies of zotero.sqlite by copying them to that location and filename". The missing information that worked me: switch off auto-sync and then change the name of the zotero.sqlite.bak file that has the collections to zotero.sqlite. Then restart Zotero.

dstillman

It's not missing — you were just looking at the wrong section. The Locating Missing Zotero Data section is for what it says: "If you open Zotero to find your library blank or missing lots of data".

The relevant information is further up the page, in Restoring Your Zotero Data From a Backup and Overwriting Synced Changes: "If you or someone else made unwanted changes to your Zotero library and synced those changes to your online library".