I/O is malfunctioning

[GCWilliams]

Hey guys!

I'm currently using Pro Tools 2018.12 on OXS 10.11.6.

I've been experiencing an issue with the I/O menu. It worked perfectly for a long time, but now here's what's happening...

I'll open a session and in each track the outputs won't be displaying and I won't be able to select any. I'll then go into the I/O menu and they appear to be setup perfectly.

Sometimes if I delete everything in there and then recreate all of them them it will begin to work. However sometimes this doesn't fix it either.

Often I'll have to create a brand new session which will work for that first time but when I reopen it I'll begin to get issues again.

Any help would be most appreciated!

Thank you,
Geoff