pdf attachments suddenly "can't be found"

matthed
Hi, a lot (but not all) of my pdf attachments suddenly can't be found. I use Zotero on my local machine and I subscribe to have it all synced up to the cloud version of Zotero too.

Here is one example... I open up a citation and click on its pdf attachment in my local library and get this error:

"""
The attached file could not be found at the following path:

/Users/mattdean/Zotero/storage/8N7UPAW9/firman_simmons_2010b.pdf

It may have been moved or deleted outside of Zotero, or, if the file was added on another computer, it may not yet have been synced to zotero.org
"""

Quick sidenote: I never moved or deleted anything. And this occurs with probably hundreds of my references.

The pdf file also does not occur on the cloud version of my synced library.

In both my local library and my cloud library (again, both synced), I see a file named, in this case, "firman_simmons_2010b.pdf", but in both cases I get the above message when I double click that file name.

However, I am a Mac OS user and have my Zotero library backed up by Time Machine. If I go into my Time Machine backup, the file is there one date, but suddenly not there in a more recent backup.

Does anyone have any advice? One thing I was thinking of doing is "merging" my current library with the version of the library that I have on my Time Machine backup. Will this work?

Thanks for any help,
Matt
  • dstillman
    It's really what the error message says — the file was moved or deleted outside of Zotero or was added on another computer and not synced. There's no code in Zotero to delete files on disk separately from items, so there's no way for this to have been caused by Zotero itself. And the file doesn't exist online — if it did, as long as you have file syncing enabled, it would be downloaded automatically when you double-clicked the file. (Seeing the attachment item online isn't the same as the file actually existing. If the latter, you'd be able to actually view it online.)

    You have about 1,000 files in your online library, all created the same day last year, that were never uploaded for some reason. It looks like you increased your storage subscription shortly after then, so generally I would say that it would be because you created them on another computer, couldn't upload them because of a quota error, and then never synced that computer after increasing your storage.

    However:
    However, I am a Mac OS user and have my Zotero library backed up by Time Machine. If I go into my Time Machine backup, the file is there one date, but suddenly not there in a more recent backup.
    This suggests that you did have the files on this computer. In that case, you likely ran some sort of disk-cleaning tool (even the built-in macOS one) to try to clear disk space and accidentally wiped out your local Zotero data and/or files. When you reopened Zotero, it would've pulled down your data and files from the online library, but anything that hadn't been uploaded wouldn't be able to be pulled down.

    You can look at the creation dates of the *.sqlite and other files in your Zotero data directory to see if there's a particular date when they were created (though it's also possible you only deleted 'storage', not the .sqlite databases).

    As for why that set of files was never uploaded, I couldn't tell you — if they really were all on this computer, it might have been some bug related to hitting the storage quota.

    In any case, to recover, you can simply 1) sync, 2) move your existing data directory out of the way, 3) restore your entire data directory from Time Machine, and 4) sync to pull down all recent changes. If the files are all available in the backup, you can do Reset File Sync History from the Sync → Reset pane of the Zotero preferences to force Zotero to check all files to see whether they've been uploaded and upload them if not.
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