O.P. Signout and the contact event viewer problem
I noticed during a script developpement that sometimes the contact information events viewer was empty.
No events from my contact list was reported. The simple fact to display and close the global event viewer makes everything working again.
So I made others investigations and I found that when when we signout/signin without quitting WLM, the contact event viewer stops working.
By quitting messenger and launching it again then it works again.
It looks like if the signout stops the event viewer but unfortunately the signin doesn't reactivate it.
The only way to bypass the problem is to display the global event viewer or to relaunch WLM.
I Have this behavior on two machines.
WLM 2011 Build 15.4.3555.308
Windows 7 Ultimate 32 and Windows 7 home premieum 64