Yesterday I had to upgrade my Mac to the latest version of Catalina and lost an entire day resolving the havoc that ensued (64-bit complications, etc). I was finally able today to get back on a session in Pro Tools but am now getting a doubling effect in my headphones on my vocal track, though nothing in my settings has changed since I last saved the session on Friday. The doubling doesn't record, only in the monitoring, even with Low Latency engaged. It's not a latency, except slightly the doubled signal. It's almost like there's a loop going on in my bus routing, but I created a new session with a single mono track for the vocal mic, no inserts or sends, still getting it. My buffer's at 32, cache is at 256. Interface is a PreSonus 32R mixer which I monitor back through. Pro Tools is 2019.

This is a new problem, and the only change in my system was the Catalina upgrade. Hoping there's a solution out there.

Thanks.

iMac (Retina 5K, 27-inch, Late 2015)
4 GHz Intel Core i7
32 GB 1867 MHz DDR3
2TB Internal Fusion Drive
2 4TB External Drives with Mirrored Backups
2 External Monitors: 27" & 65"