My front-end freezes as soon as I type more than two letters in a notebook. I think the error occurs, when the auto-complete feature kicks in. If Mathematica was started from a terminal, the following text is shown.

Mathematica has received the signal: SIGSEGV and has exited.
If possible, please report this problem to [email protected]
describing in as much detail as possible what you were doing
when the problem occurred.

I use Mathematica 10.3 on Ubuntu 12.04. Rebooting and -cleanstart did not help. This installation worked fine for quite some time, but suddenly this problem appeared.

Is this a known problem? Before I contact the official support, I want to make sure that there is no trivial fix.