[MacTUG] UserEventAgent process hanging, causing system slowdown

[Marlon A. Griffith]

As we've noted a number of times, it's a good idea to routinely fire 
up Activity Monitor (located in /Applications/Utilities) and check 
for rogue processes that are spiking in processor usage, hanging 
(displayed in red type), or otherwise abnormal (see this tutorial for 
more information on what types of processes to look for and how to 
end them).

During such routine inspections, a number of users have found the 
process UserEventAgent hanging or exhibiting inordinately high 
processor usage. UserEventAgent is one of the processes launched 
automatically in Leopard by launchd, as described in this article, 
http://www.macfixit.com/article.php?story=20071129113753285. It's 
used to handle interaction with various device drivers, and as such, 
is prone to hangs, spikes in processor usage and other issues caused 
by potentially faulty devices or device drivers.

For instance, several users have reported that simply disconnecting 
offending causes the UserEventAgent to resume normal operation or at 
least stop hogging processor time. In other cases, actual drivers 
must be removed. A number of users have fingered audio-related 
plug-ins, such as those located in:

    * /Library/Audio/Plug ins/

So check Activity Monitor for potential misbehavior of this process 
and suspect third-party device drivers and/or devices themselves as 
the culprits.

http://www.macfixit.com/article.php?story=20071207101723882