Clicks and Pops in PT12 (No hardware, no plug ins)

Hi all,

Just installed Pro Tools 12, created a new session with one mono track, and am just playing around with a guitar through the built-in line in on my Mac. No hardware, no plug-ins.

I'm getting a bunch of clicks and pops on the track. The same is true if I open an old session and play it back.

I've allocated a larger buffer size and cache size, but neither has done the trick. Could this be an indicator of insufficient RAM? I've got the latest OS with 4 gb RAM at 2.2 ghz.

Thanks!

Clicks and Pops in PT12 (No hardware, no plug ins)