On 'certain' imported 8.53 imported projects, iirc.  (but I haven't isolated the bug).  (Yeah, I know its not wise to import 8.53 projects, but I'm hard-headed)

Its not the SoundCard (latest drivers on 2 cards I've tested).

I wonder if its Sonitus EQ or a 3rd party VST or such.

Recovery requires disconnecting and reconnecting the soundcard TWICE (Octa-capture or UA-4FX in my case).

Any thoughts (great or small) as to what issues may cause X2a to crash on save with certain imported projects?  Thanks!

Hi Philip ! 

You could try "importing" your 8.53 project in safe mode in X2.. 

(file--OPEN-- select file, then SHIFT-CLICK on OPEN)

click NO TO ALL, to disable any plugin used in the project, 

try to save.. if it saves successfully, then it prooves your problem indeed lies in a plugin. 

Don't hesitate to report back if you succed, or not ! 

Cheers ! 

V

Firmware?

I have had plug ins do this to me on upgrades. Usually it is a 32 bit bridged plugin that causes the problem.
 
You can also try loading your project normally and stop the audio engine before saving. The button for this is on the lower left of the transport section of the control bar.