Disabling subtitles - rightclick video during playing and uncheck Subtitles -> Enable. It will disable subtitles in MM (and the setting is permament). But note, it will disable subtitles displayed by subtitle plugin from MM codec pack, it will not affect external subtitle tools.
Also try latest MM4.1 Beta with latest codec pack.

Are you running the codec from MM? If not give that a try. There is a 30 day trial pack available. VCL etc have their own codecs and that might be why they dont go out of sync. I know since i started using the MM codecs this happens very very seldom.

Also, for those files that i do not rip myself from my dvds I convert to a specific mp4 format with DVD Catalyst 4. I convert them to this format because it is much more usable between smart tv/blu-ray and Samsung Note 10.1, phone and daughters ipad.

Hope this hepls

I'd say 75% of the time while watching a video, the audio will gradually become out of sync. The same does not happen with VLC or MPC for the same files. Is there a fix for this?

Also, I know it's a minor issue but when watching video is there any way to auto-disable subtitles from appearing?

Thanks!