com.apple.authd & syslogd heating up my system

Hi,

after updating my MBP (mid 2009) to 10.9.1 my user (=admin) showed some strange habbits.

First my keychain seems to went crazy, all the time my system asked me for the password to my local keychain for which none of my Passwords (log-in PW or admin) worked. After searching for advise I deleted the whole keychain from my user and created a new one.

Now the com.apple.authd created tons (I estimate 2000 per second) of the same error messages, which boos my cpu-usage to 100% on both cores and results in enough heat to boil water for my tea on my MBP.

Here is the error message from console

26.12.13 20:05:38,319 com.apple.authd[36]: assertion failed: 13B42: libxpc.dylib + 26642 [4554927A-9467-365C-91F1-5A116989DD7F]: 0xf

This problems shows up even when I am logged in as a different user.

Has anyone an idea?

Thanks in advance

Sebastian