Unwanted and unexpected logout/reboot

Hello everyone,

I've got a very strange and annoying problem. My Macbook Pro tries to shut itself down (logout etc.) almost everytime I leave it running without using it for more than an hour or so... Very often I get back to the machine, for example after lunch break to find that it has tried to shut itself down. How I know that is because I get the error message explaining to me that one application (different ones all the time) refused to quit and thus prevented logout (timeout).

I've checked for messages in the console (logs) but there is just nothing at all! The only thing that might have something to do with it is this log entry: [0x0-0x308308].com.operasoftware.Opera[29836] Unknown argument: -psn_0_3179272

I'm not sure it's got anything to do with the problem, it might just be another symptom...

Does anyone have an idea what the problem might be? It's really quite annoying because it sometimes succeeds in rebooting the machine and even if not at least quits a few applications!

This problem never occurs when I actually use the machine...

Thanks in advance!

Have you checked the security settings in System preferences? It may be set to logout at a specific time.

THANKS!

I can't believe it was such a stupid setting... It was set to log out after 60 minutes of inactivity. Was this setting introduced with an update and activated by default? I don't remember setting this up...

Anyway, problem solved, thank you so much.