instrument tracks not playing

[mattrussell]

did some searching on this and didn't find much info, but forgive me if i just didn't see something obvious...

i record a lot of electronica and i use pro tools. have been a user since V3. haven't seen this one before in all of the years i've been using it.

i spent friday night recording an artist and we used 4-6 instrument tracks, (mostly omnisphere) - simple pads and light movement on acoustic guitar music. i didn't print the sounds to actual tracks, i just left them as instrument tracks as we wanted to do some midi editing the next morning.

we returned to the studio saturday morning and the instrument tracks were not working right. one wouldn't play at all no matter what i did and all of the others were playing the first one's midi data - all at the same time. a virtual train wreck.

i was able to open new instrument tracks, copy the midi data i had from each of the original ones to new ones and boom, everything came back and worked fine. we had worked on two songs and this occurred on both of them. from that point on, no problems. we took a lunch and i shut down everything, left for over an hour, came back and still no trouble.

now then, it's sunday morning and i just put the artist on a bus back to nyc, i shot home and opened the sessions and guess what? it happened again only this time, we have a lot more going on. i again copied all the midi onto new ones and it's all working (this time i used midi tracks with my instruments on auxes as i want to solve this before using instrument tracks again).

i'm about to print everything to tracks as it's all "done", but can anyone tell what i'm doing wrong?

both my home machine and studio machines are the same: mac pros running 10.6.8 and HD 9.05. all the same plugs, all up to date.

thanks, m.