Although I had been successful in recording 22 tracks at 24/96 with Pro Tools 9 (MacBook Pro latest version external 7200 HD on expresscard IDE buss) upon upgrade to version 10 I began to have frequent stoppages while recording.  All my recording is live with no playback to the musicians. So I had my UFX expert disable the routing of playback data to Pro Tools (previously used to male a temp mix in playback). This helped a lot! Because, I assume, Pro Tools was born as a playback/post program and never "Grew Up" as a record program. Your record settings are made in the "PlayBack Engine" (after several tries I have settled on 8 processors, 90% CPU, maximum latency/max buffer size and a big cache #) there's no seperate "Record Engine. So, obviously, Version 10 is cranky while writing the same amount of data as version 9.

There's also another Pro Tools 10 quirk: There seems to be some "File Overhead" that's necessary to write even after you have stopped recording. I record in 45-60 minute live chunks.  After stopping, ProTools ties up the hard drive for 4-5 minutes before it will allow recording to restart.  This interval is less for a smaller "roll" but still significantly frustrating-especially after Pro Tools stops mid session because the best you can hope for is to capture the next, approx 3 minute, tune. Interestingly, if you open a fresh session you can record immediately but, upon reopening the old session, you must wait for the unwritten "File Overhead" to finish before you can either Playback or Record.

After saving a recorded Pro Tools file with the "Overhead" still writing you can close Pro Tools without a "Save" prompt-indeed if you wish to save such a file (previously saved after coming out of Record) you must do a "Save As." This is why I call it File Overhead because all the recording data has been captured and the Overhead data is durable-even if interrupted by program shutdown. This is then, to me, a mark of really buggy, junk software. Fundamentally, Pro Tools appears to be a giant work around for live recording. Apologies for my less than sophisticated knowledge of software but I continue to be dismayed at Pro Tools' primitive code and, eternally, grateful for the stability and support for my two UFXs.