[delta]

Firstly Thank you Darryl for taking the time to give such a detailed response.So here's the update. The suspect drive in the first G5 did fail with disk utiity unable to repair. I have replaced it and cloned from the startup disk in the second machine and everything seems to be working fine on the 1st G5.hooray.

The second machine still not right. I have erased one of the internal drives and cloned it from the now working first G5. I have also erased the internal drive reinstalled OSX 10.4 and protools. Neither of these actions has helped. The album session can't get past "activating inserts" on opening the session(it will load without plugins). Also if I open a new session it opens fine but if I put multiple tracks into record I get at least a minute of spinning beachball before it starts recording. Same if i just hit play. Only when multiple tracks are in record though. Maybe this tells you something?

Being such an old system my safety net is to have a second G5 to swap out if I have issues with the first mid-session with clients. It has worked well for a few years. So although I now have a working G5 the second G5 is still having the issues described above. I maybe wrongly assuming that the original issue was a damaged start up disk but by replacing and cloning it seems to have resolved issues. What is puzzling me is that I cloned it from the second G5s startup disk which has actually still got issues described.

All pro tools session run from external Glyph firewire drives.Not sure "what file system is on these drives" but again I am swapping them between whichever G5 I am using. Apologies for the language ignorance!

You are talking about "start up disk directory" is damaged? You mean the /boot directory? Your home directory? not sure I understand this question. Start up disk as in the disk I select in system prefs to start the machine from.

I hope this is understanble, please excuse my lack of understanding of the mac details!