Too Many disk I/O tasks (-10022) error playing song after edits

Question

I have been fighting Logic 9 throwing the "Too Many disk I/O tasks (Elastic Audio) (-10022)" error when playing back a song with 12 tracks of audio AFTER I cut across 8 tracks (of drums) and move regions around. The Disk I/O indicator never shows more than 1-2 bars, tops when this error is thrown. While writing this up and troubleshooting, the problem has seemed to sort itself out, but only after doing some peculiar steps.
*System is MacPro 2x2.26 Quad-Core, 8GB RAM, Mackie Onyx 1620 recording to 500GB WD MyBook Pro over FW800. I/O Buffer = 128.
1) Grouped the 8 tracks of drums (there are 3 takes on each track). Play back song. No problems.
2) Cut the drums at bars 73, 81, 105 and 109.
3) Drag-copied the regions from bars 105-109 to 73-81.
4) Playback song, error thrown at bar 70
5) Increase buffer size to 256.
6) Playback song, error thrown at bar 70
7) Increase buffer size to 512.
8) Playback song, error thrown at bar 70
- Thought this might be a disk problem.
9) I copied the project with all the files to the internal Seagate and open the project.
10) Playback song, error thrown at bar 70
- Thinking this is not a disk problem.
11) Open the project on the original WD external drive.
12) Mute all regions an all drum tracks except the kick.
13) The song plays back normally.
14) Un-mute regions on 1 track and playback and repeat for each track.
15) The song plays back normally until the 8th drum track is un-muted, then the error is thrown.
16) Mute and un-mute the regions on 8th drum track.
17) The song now plays back normally. Error no longer thrown.
Looks like after making the edits, muting all the regions and un-muting them 1 by one might have cleared this up right away.
Is anyone else is experiencing something similar? If so, how are you working around this?

Answer 1

No, didn't solve it yet, after I'm done completing work to meet a deadline, I will do some experimenting and see what I can figure out. But so far I've had this phasing issue occur in two different sessions on two different rigs (both Mac Pro dual-quad core with lotsa RAM)...
One test that anyone could try... to really max it out... take one single source and record it onto 20 tracks at once... or I guess you could just record one track and then duplicate it 19 times, whatever. Group all these tracks, keep `em all at the same level. Then take a listen to all tracks at once using some good headphones.
Then put all the tracks in flex mode and do some flexing, flex every single quarter note this way and that way for three full measures or so, whatever. Then play it back again with headphones. If you hear ANY hint of phase shifting, then you are experiencing what I am experiencing.
For anyone who might not be familiar with the "phase shifting" sound I speak of, it pretty much will sound as if you are running your tracks through a classic "phase shifter" effect pedal or whatever. If using headphones, it'll seem like the audio starts swirling around in your head like some wacky stereo effect, frequency response will change and shift, etc.
I've noted that I have not always heard phase issues when flexing, it seem to be a bit inconsistent. It may be because I've been working in some very large sessions, maybe in my situations Logic was already being heavily taxed and then the extra flexing just put it over the edge. Don't know. Will do some testing perhaps next week.
But, I'd say everyone should be careful about this before bouncing forever to disk and then maybe deleting all your old raw audio, because if you permanently write in some wacky phase shifting between your group of drum tracks and have no original raw files left, you'll be in very big trouble... I don't think there would be any way to fix that. In a professional level mix, that type of issue would stick out like a sore thumb. I guess one fix would be to apply a phase shifter effect across the entire drum bus... on purpose... as some sort of artistic statement... hey, it might sound cool!
This whole issue has made me realize how incredibly important it is for DAW tracks to remain truly phase locked at all times. Been working with DAWs for years now and never really thought about it. In one regard, this is a lot to ask... to make sure your 30-odd tracks or whatever are always dead in time with each other, to the sample. It's certainly of critical importance, at least for multiple tracks of the same exact source (like when you have 12 mics on a drum kit etc).
Actually, perfect time synch is just as critical for even a mere TWO mics on a given source... any stereo recording. Once one track goes out of "synch" with the other, even by a minute amount, just for a short amount of time, you will HEAR it.,.. and it won't be good... unless you desire a wacky phase shifting effect.