I am using MC 3.0 with all keys mapped to the default settings. For some reason MC wants to constantly put me into trim mode and move back to a previous edit point. This can happen when I click on a part of the timeline, hit the add edit key, add a key frame or hit move forward 1 frame. I am aware this is by design if you use FF/REW but why is it doing it for all of the things mentioned above? Its hard to get anything when it randomly decides I want to trim. Please help! 

 You can try deleting and rebuilding the site settings files, when corrupted they can cause toolsets to behave erratically. Quit the app and from the main settings folder, delete the following: MC State, Site_Settings, Site_Attributes. On re-launch, the system will detect  the missing files and build new ones.

I had this problem in MC 2.X before when I had Slingplayer running in the background.

Strange but true.

 Thanks Larry, I deleted 2 of the files but I cannot find MC State. Could you tell me what folder it is in?

C:\Program Files\Avid\Avid Media Composer\Settings

 As Randall said....