Logic Pro X Crazy Issue Please Help!

Hi

I own a 21.5" Late 2013 iMac 2.7GHz 16 RAM, a Lexicon Lambda Interface and JBL monitors connected to the Lambda. I've been using this setup with the Logic Pro X for the last year or so and it worked great. About a month ago I started using a few Plugins from Waves on my projects. It worked completely fine, too. In the last week I started working on a big project with many tracks. Then I turned on few of the plugins (Abbey Road Plates for that matter). Suddenly, when I started playing the tracks, the software made a weird horrible slow-motion clipping sound, following the message:"Error while trying to synchronize Audio and MIDI. Sample Rate 21754 recognised. Check conflict between Logic Pro X and external device."

When I stopped playing, the tracks started playing by themselves with a slight delay for a few seconds, then stopped. I tried turning off all the plugins, but it ended up with the same issue. I then searched online for a solution, and I found that cranking up the I/O buffer size helps, and so I did cranked it from 256 to 512. It didn't help. So I tried cranking it to 1024. Didn't help either. I then tried cranking it down, and guess what? IT DID NOT HELP A BIT.

I searched for other solutions like deleting a "plist" logic file from the library etc. and tried them all and nothing helped. Tried restarting Logic, my Mac, reconnecting the Lambda and so on. I'm stuck with the most frustrating issue I've ever had with no clue of what's causing it and it's driving me nuts.

Any help is blessed.

Sincerely,

Elay