Restart Firefox and provide a Debug ID for a sync attempt that stalls.

I've removed another folder and restarted it has copied another 25 folders and seems to be getting stuck on a 2.4 MB scaned pdf (I know for sure that it is scanned due to the text not being straight across the page.) I'll give it a few more minutes (debug is runnning) and post that up.

I think I know which folder it is getting stuck on as it appers to be picking up the folders from the ../storage floder in alphabetical order, so checking the zotero folder on the WebDav server makes it easy. And on the first one I deleted the last folder copied and it still got stuck so , it looks like the folder it is getting stuck on is the one after the last successfully copied.

I've got most of the files to sync by moving the folders that seemed to be causing the problem. Thirteen folders had to be moved. File synch completes with one remaining but I do not know which file it is. The last file in the directory by alphabet has synched.

The thirteen files are all 1.7 MB or bigger (but at least one 2 MB file synched OK). They are pdfs of government reports, one thesis, and two scanned papers.

Anything else I should look at or do?

It struck me as surprising that a connection error consistently happens with the same files, especially as the server is coping with files 10 times the size. So, I've tried a few things.

Turned the security software off. No difference.
Tried using my mobile network, again no difference.

Some more information. I've managed to get two of the folders to synch (I guess that these were network errors) and have cleared out another (it was in the trash anyway). This leaves ten references. Nine of them were created as part of a batch transfer from Reference Manager. The other references in the same batch all synch without any problem.

Two of them I have redownloaded from source. One seems to have gone into the library and synched. This one zotero could seethatthere was a reference on the web page and I clicked the icon in the URL bar. The other was a pdf that opened in a window and I had to select 'Create New Item from Current Page' and manually create the parent item.

THe Debug file D1274313309 was created during the synch after zotero had got stuck and I'd closed and reopened zotero. Note that entity AWSNZ83G and KF89QTWH are both from >3Mb pdf files of scanned reports.

Is there a workaround for this? For example, for these files create the zip and prop files and manually upload to the webdav directory?

It struck me as surprising that a connection error consistently happens with the same files

By calling it a "connection eroror" I'm basically just saying I don't think this is a bug in Zotero itself, not that it's not related to specific files.

For what it's worth, in your debug output there are lots of lines like this:

(2)(+0000058): progressMax has changed from 5020457 to 4597140 for request 'null/KF89QTWH'

(3)(+0021907): Invalid progress for request 'null/KF89QTWH' (32768 < 4489216)

(3)(+0000000): Invalid progress for request 'null/KF89QTWH' (98304 < 4489216)

(3)(+0000001): Invalid progress for request 'null/KF89QTWH' (131072 < 4489216)
Zotero outputs this when it gets unexpected progress values during a request. This is likely either a Mozilla bug or a problem with the computer/network/server, or a combination of the two, but it would take some digging around in the code by someone able to reproduce it to know more. That's probably not something we can help you with, I'm afraid—Zotero works with standard WebDAV servers and with Zotero File Storage, and we don't have the time to debug problems with individual servers. But if you upload an example file somewhere and provide a link to it, someone might be willing to try to reproduce this with CloudMe.

Is there a workaround for this? For example, for these files create the zip and prop files and manually upload to the webdav directory?

Not easily.

No need to start a new thread.