Missing attachments

jsdodge

I use Zotero Storage with a 6GB plan and my current usage is at 67%. Frequently I discover that an attachment is missing from my local storage. In my Web Library on Zotero Storage, the file name appears in the attachment panel but the interface does not provide an option to download it, indicating that the file does not exist on the remote server, either. Normally when this happens, I just download the file again and reattach it to the reference, but this isn't a stable solution. Can anyone offer help with debugging this problem?

jsdodge

PS: I noticed that my local Zotero/storage directory has 6.8 GB, which is nominally over my 6 GB storage limit. When I check on Zotero Storage, however, it indicates that I am only using about 4 GB.

adamsmith

Are you only using Zotero on one comput? The typical scenario would be that you added the item in a different machine and sync failed

jsdodge

Yes, I just use one computer, and the files are in my personal library. I have a few group libraries, but the other members of my research group don't tend to use this service.

dstillman

What's the zotero.org URL from the web library when you click on one of these items?

What you describe isn't possible with Zotero itself. If you add a file on one computer, the file will always exist there, unless you or something else deletes it from outside of Zotero. There's literally no code in Zotero that would delete a file separately from the attachment item. (A future version of Zotero will make it possible to configure how long local copies of files should be kept in order to save disk space, but that's not out yet, and it would only apply to files that had been uploaded in any case.)

If a file doesn't exist, and it also doesn't exist online, it was almost certainly added on another device. It looks like you have used the iOS app, which counts as a "computer" in this case. So you'd want to check the files there.

(You also appear to have been using ZotFile in the past. We can't vouch for anything ZotFile might have done.)

jsdodge

Here's one:
https://www.zotero.org/jsdodge/items/Y5WUWMCG/item-list

Thanks for clarifying the way things work. I just checked on my iOS device and the above file isn't there, either.

It's entirely possible that something other than Zotero caused this—I'm just looking for a way forward. I encounter missing attachments infrequently, so it's possible that they were lost at a discrete moment in the past and the problem is not ongoing. I'll remove ZotFile, for starters. Is there a way that I can purge the missing attachment links while leaving the parent references intact? If it's not an ongoing problem, then I can just reattach the PDFs as needed.

dstillman

Did you previously or do you currently have Zotero configured to use WebDAV syncing on any of your devices?

Did you use "Purge Storage in My Library" from your storage settings online at some point?

I believe those are the only two possibilities for the state of the file online — details about the file exist, but the file itself doesn't.

That file hasn't been updated in 2019, so this might have been something you did years ago.

jsdodge

I did use WebDAV before, but haven’t since I switched to Zotero Storage. I don’t believe I used Purge Storage in My Library. It’s entirely possible that I did something inadvertently—I had a hardware failure a few years ago that required me to recover a lot of things from backups, and I think the problems with Zotero began afterwards.

At this point, I’m less concerned with how it happened and would like to know if there is a way to automatically find and delete stale file references. Ideally, I’d back up my local library, purge the stale references from the remote, then overwrite my local library with the remote copy. I’d keep the backup in case the remote is missing references to files that are actually in my local library. Is this possible?