I've noticed that nearly every day SEP slows my computer, and it seems to be caused by it automatically running a Defwatch Scan...which seems to be occurring after receiving new definitions. I searched the forum and found a previous post regarding this issue (https://www-secure.symantec.com/connect/forums/sep-121-defwatch-scan).
Since I'm running a version above 10.1.x, it sounds like I should be able to prevent this from happening without having to go into the registry. However, the menus, etc., described in the instructions don't seem to be the same as those I see in SEP. By looking around, I was able to find what I think to be the setting described. Here's what I've done: Antivirus and Antispyware Protection > Options > Change Settings. Under the File System Auto-Protect tab, click Advanced, under File cache there's a checkbox for "Rescan the cache when new definitions load".
I unchecked this box yesterday, and yet the Defwatch Scan initiated today after receiving new definitions again. Is this the wrong setting? Do I need to go the route of messing with the registry (I've been avoiding that since I'm not too tech saavy and don't want to screw anything up)?
(Edit: Added clarification.)