Popup keeps informing me on error

[Screenlink2015]

Hello, i have a removed a complete folder with files in my desktop client.
When i use the browser to check the files, i see the complete folder and files arestill in this webclient.
I cannot remove them, it gives an error: "error when removing folder"
When i check with an ftp-client the datafolder, the folder is gone.

every 5 minutes i get an popup that the system cannot sync.....
I'm using owncloud 8

How can i remove this folder in the webclient to stop these annoiying popups?

[Screenlink2015]

This is the message i get in the windows desktop client:\

[tflidd]

You can re-run a file scan on your user-folder:
https://doc.owncloud.org/server/8.2/admin_manual/configuration_server/occ_command.html?highlight=occ#file-operations

For locking issues in general:

File is locked - how to unlock

You can't access files because they are locked and you find such errors in your logfile: {"reqId":"0DijSqEkfOg2iyh9VD8J","remoteAddr":"xx.xx.xx.xx","app":"webdav","message":"Exception: {\"Message\":\"HTTP\\\/1.1 423 \\\"path\\\/file.extension\\\" is locked\",\"Exception\":\"OCA\\\\DAV\\\\Connector\\\\Sabre\\\\Exception\\\\FileLocked\",\"Code\":0,\"Trace\":\"#0 If you're running the ownCloud 8.2.x branch make sure that you're using at least 8.2.2 (previous versions had a bug causing this iss…

I'm using owncloud 8

Any of the 8.x versions is not supported any more, you should upgrade to a current still supported version (at least 9.0): https://owncloud.org/changelog/

[Screenlink2015]

Thanks for the fast reply ; i'm gonna upgrade to V9 first