Known Bugs and Work­arounds

At times there are issues that we cannot correct on our side for various reasons out of our hands. This page collects information on these in addition to known workarounds, for your benefit.

Most common cause: Quota full

One cause of failing logins is a full disk quota. Every user has 1GB of space available in their home directory. If this space is filled, no further files may be created. This usually causes graphical Desktop Environments (KDE/Gnome) to fail to start, as these can't create temporary files needed for their startup and operation.

You can still log in via console. Press Ctrl + Alt + F2 to switch to a console. Then, follow these steps:

  1. Log in with your IMT credentials
  2. Enter `df -h $HOME` to view your current quota usage. "Use%" close to 100% indicates a full quota.
  3. Enter `ncdu` to discover and possibly delete large files and folders in your home directory. (Press `?` for help)
  4. Enter `exit` to log out after you've reduced your quota usage by deleting files.
  5. Return to the graphical desktop by pressing Ctrl + Alt + F7

Which types of files commonly cause a full quota?

  • Caches of browsers like Firefox oder Chromium. We recommend to configure your browser to delete its Caches when closing your browser.
  • Large downloads.
  • Video recordings of lecutures.

Please contact the IMT if you require more space because you, for example, collaborate on a larger project. The IMT manages the fileserver.

Less common causes

There's a series of possible other causes for problems with logging in. We have listed a few common causes below.

Please don't hestistate to contact us if you would like help with diagnosing or fixing your login problems.

  • "IT-Services for CS" not enabled
    • Users require an IMT account with active "IT-Services for CS" ("IT-Diensten für Informatiker"). We decribe how this can be enabled on this page.
  • Worstation is disconnected from the network or broken
    • Please inform us by mail if you suspect that one of our workstations is broken. Please include the Workstation's name or exact position in room. We ask that you do not attempt fixing Workstations yourself.
  • Server Downtime
    • No logins are possible on any workstation while the account or file servers are down. Please consult the IMT status page for current issues and maintanance windows.
  • Password too old
    • In rare cases, your password will not be accepted on any workstation. This exclusively affects very old accounts. Resetting your password in the IMT ServicePortal can help.
  • Account disabled
    • In rare cases, an administrator may have disabled your account. Contact us if you suspect this to be the case.
  • Worstation has been reserved
    • We reserve individual workstations or pool rooms at times to run, for example, larger simulations. Please use a different computer instead.
  • Desktop configs broken
    • Desktop Environments (KDE/Gnome) may have configuration and state files that are corrupt or too old. Follow the instructions marked "Logging into KDE Session only shows a Blank Desktop Background" on this page to fix this.

There have been spurious reports of KDE issues these past few weeks. The symption is, that the default KDE session only shows the desktop background after logging in. The source of these issues are incompatibility issues with old KDE configuration files in your home directory. Deleting these solves the issue, but also deletes all your personal KDE preferences, including Kwallet passwords.

If you still mean to apply the workaround, you should delete these folders (backing them up first!):

  • ~/.cache
  • ~/.kde
  • ~/.local/share/kded5
  • ~/.config/plasma*

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