Your account is most likely over its disk quota, and your X-window session cannot write any files into your home directory.

To fix:

* Log into the system via the console (press CTRL-ALT-F2)
* ssh to bohr.
* Type the command 'quota -v'.
* Find the files that are using all your space with the 'du' command. (type 'man du' for information on usage)
* Remove, move away, or compress files such that you are below your quota.
* You can switch back to the X-Window login by pressing CTR…
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