510 Not Extended

After fresh installation of Owncloud on shared hosting server, the Desktop App (2.6.3) tries to send all files to the server. It works with most of the files, but many (>100) files don’t go up, an error is displayed: Server answered with “510 not Extended” to "PUT https://owncloud.homepage.ch/remote.php/dav/uploads/user/…/0000000000000000.
Oddly, I can upload the file in the browser-App (same folder source) without any problem.
The files seem to be randomly selected (jpg, pdf, exe, mp3, mp4, avi, mov…), large and small size, old and newer - I could not find any pattern, which files go and which do not go to the server.
By the way: same behavior when I start the synchronisation from an other PC.

Any ideas?
Thanks for your help!

Expected behaviour

Desktop App should upload all files after new installation of owncloud on server.

Actual behaviour

Some “randomly selected” files are not uploaded, Error 510 Not Extended

Steps to reproduce

  1. new server installation
  2. new desktop installation
  3. move all folders and files from the old owncloud folder to the new one

Server configuration

Operating system:

Web server:


PHP version: 7.2

ownCloud version: 10.5.0

Storage backend (external storage):

Client configuration

Client version: 2.6.3

Operating system: Windows 10 Home x64

OS language:

Qt version used by client package (Linux only, see also Settings dialog):

Client package (From ownCloud or distro) (Linux only):

Installation path of client:


Please use Gist (https://gist.github.com/) or a similar code paster for longer

Template for output < 10 lines

  1. Client logfile: Output of owncloud --logwindow or owncloud --logfile log.txt
    (On Windows using cmd.exe, you might need to first cd into the ownCloud directory)
    (See also http://doc.owncloud.org/desktop/2.2/troubleshooting.html#client-logfile )

  2. Web server error log:

  3. Server logfile: ownCloud log (data/owncloud.log):

Config report: config_report_20201028.txt (307.1 KB)


It seems to be a security rules issue …
Could you please attach a screenshot showing the error ?
Please attach also your web Server error log and ownCloud logs

Thanks !

1 Like

Thanks, Aki.
Luckily the problem was solved after syncing all my other devices (work, laptop etc.) - these did not have the problem…

Best regards!


I am also observing the “510 not extended” issue, and I can work it out.

For me, this started when the server system at my hosting provided was updated. Before I had OwnCloud 8.2, now I have I am running the OwnCloud desktop client 2.6.3 on Debian Linux. I keep seeing sync failures like this (there are hundreds of these messages):

Server replied “510 Not Extended” to “PUT https://myhost.com/owncloud/remote.php/dav/uploads/username/3431728463/0000000000000000

What can I do about this?

1 Like

I have the same problem. First, I thought, it would be all exe-files. But then I zipped a File of about 70MB. And the ZIP did not pass either. Secondly I split the file into 10MB Zips and they did not pass neither. Only the 1,3 MB leftover was transmitted. So it has to be a time-out problem… That would fit the Not Extended message.

The solution is to disable ModSecurity on the server side. I could not change the settings at my host backend in detail, so I had to completely disable it. Maybe there is a way to allow the PUT command for certain file extensions or file sizes respectively.