I've also had trouble running 33 on Sierra. I had previously posted about my problems but can't find that post, so I apologize for the duplication. I Probably posted in the wrong place. Sorry. I'm afraid I don't understand the Media Center well enough to be helped, but I'll give it one more try.
I am trying to run MC 33 on a Macbook M1, and just get beach balls. I done all the OS stuff, including reinstalling sierra 5.1. I suspect the problem might be network access. I have never noticed MC requesting network access, but guess it did and I missed the boat because MC is not listed as an OS setting option in all access.
A little more background on my experience with MC. I've run it for years with few problems until now. I am currently running MC 33 on an intel Mac mini as a library server running Mac Senoma 14.7. That's still working OK. Before I (accidentally) upgraded my MacBook to 15.1, I was running MC 29 and using it to access the server. Now I can't get MC 33 to run on my MacBook. My MacBook is set to allow software from any source to run, so that's not the problem. MC also has full disk access permissions. Network access is the only permission not allowed, asfak. Sorry if I am not doing everything right on the forum. Hope for some tolerance and patience. I would appreciate any help or suggestions. Thank you.