I upgraded to 12 on 9/5 and have had these problems:
High and growing memory usage... 11 to 12 mb at boot and then moving upwards.
Frequent "hanging" of DO and nearly every program except Task Manager. "Processing" icon spins for 5 to 20 seconds.
I tried disabling the dopusrt app does not help.
reverting to 11 resolved these issues. I have 11 currently running.
OS is Win 7 64 bit with updates all current.
System is Asus X99 based with 64gb system memory and i7 5280. Boot drive is Samsung EVO 850 4gb.
Please try How to find components causing memory leaks to see if it identifies where the leak is coming from.
It is often from a shell extension and not part of Opus itself, although both are possible and have happened.
Thanks. The bigger issue is that with 12 installed, the whole system stops responding for between 5 and 20" at random, about 25 to 30 times an hour. Removing 12 and reverting to 11 resolves that issue.
It's almost impossible for Opus to affect other programs in the way you describe. Maybe try disabling your anti-virus software and see if that makes a difference?
Check the system logs in Event Viewer as well. They helped me track down similar freezes which started after installing the Windows 10 Anniversary Update (due to a new storage driver that kept trying to put my SSD into a low-power state it doesn't support).