You deleted all collections and items in your library 24 hours ago.
Did you run Replace Online Library from an empty library? Because that would certainly do it. This would absolutely not happen if you just set up a syncing in a new OS account and synced — that would just pull down your existing online library.
In any case, if you have a version of your database with your data before syncing, see Restoring Your Zotero Data From a Backup and Overwriting Synced Changes. Any attachments might be gone, though if you were using Zotero Storage we could relink any files that had been previously uploaded.
Yes, I think I did! I downloaded Zotero to the new profile and thought I was replacing with the online library. But it obviously meant replace with the empty one. I will give this a go.
Ok thank you!!! I now have my data on the computer database, however when I try to sync it to the online one it goes back to the blank one. How do I sync the database on the computer to online one? Incase this happens again?
If you were using Zotero syncing, you can just set up syncing with the same account you were using previously and sync.
Otherwise, your data would only be in the Zotero data directory you were using previously.
There is nothing to sync now the data is gone from both.
I found the data directory but it uploads then disappears again.
Did you run Replace Online Library from an empty library? Because that would certainly do it. This would absolutely not happen if you just set up a syncing in a new OS account and synced — that would just pull down your existing online library.
In any case, if you have a version of your database with your data before syncing, see Restoring Your Zotero Data From a Backup and Overwriting Synced Changes. Any attachments might be gone, though if you were using Zotero Storage we could relink any files that had been previously uploaded.