WebDav between Win10 & NC crashed, now unstable

Nextcloud version (eg, 10.0.2): 11.0.1
Operating system and version (eg, Ubuntu 16.04): U 16.04
Apache or nginx version (eg, Apache 2.4.25): 2.4.18
PHP version (eg, 5.6): 7.0
Is this the first time you’ve seen this error: Yup

The issue you are facing:

I attempted a copy of around 30GB over webdav through LAN from my desktop to the NC server. After a while it became somewhat unresponsive and suddenly ended as though it’d completed successfully.


  • Almost half of the uploaded files showed 0KB
  • The webdav connection (made semi-permanent using add map network drive) became inaccessible.

So I rebooted the NC server, the Apache proxy and my desktop, however now although everything else appears to be working fine, Windows 10 Pro gives me this error when occasionally attempting to add the webdav drive via map network drive again:

It appears to be unstable, and I’m not sure why.

Logs are mostly filled with:

Sabre\DAV\Exception\NotAuthenticated: HTTP/1.1 401 No 'Authorization: Basic' header found. Either the client didn't send one, or the server is misconfigured
[internal function] Sabre\DAV\Auth\Plugin->beforeMethod(Object(Sabre\HTTP\Request), Object(Sabre\HTTP\Response))
/var/www/html/3rdparty/sabre/event/lib/EventEmitterTrait.php - line 105: call_user_func_array(Array, Array)
/var/www/html/3rdparty/sabre/dav/lib/DAV/Server.php - line 466: Sabre\Event\EventEmitter->emit('beforeMethod', Array)
/var/www/html/3rdparty/sabre/dav/lib/DAV/Server.php - line 254: Sabre\DAV\Server- >invokeMethod(Object(Sabre\HTTP\Request), Object(Sabre\HTTP\Response))
/var/www/html/apps/dav/appinfo/v1/webdav.php - line 60: Sabre\DAV\Server->exec()
/var/www/html/remote.php - line 165: require_once('/var/www/html/a...')

And more importantly:

webdav	Sabre\DAV\Exception: HTTP/1.1 500 No subsystem set a valid HTTP status code. Something must have interrupted the request without providing further detail.
/var/www/html/3rdparty/sabre/dav/lib/DAV/Server.php - line 254: Sabre\DAV\Server->invokeMethod(Object(Sabre\HTTP\Request), Object(Sabre\HTTP\Response))
/var/www/html/apps/dav/appinfo/v1/webdav.php - line 60: Sabre\DAV\Server->exec()
/var/www/html/remote.php - line 165: require_once('/var/www/html/a...')

Even with it back up and running, it’s super flaky.

This shows up the moment I drag a folder across to the webdav drive: