Pro Tools relaunch crash

[filmixer]

Having problem of Pro Tools 5.3.1cs7 crashing if I quit and then try to relaunch. I get Type 1, 3 or 10 error code (memory address problem or init/extension conflict). The system has worked fine in the past. I've tried swapping around RAM, trashed all Pro Tools related prefs including sound manager, reinstalled PT application and DAE etc. System works perfectly after a reboot but this crashing is a pain. PT 6.1 works fine. Anybody have any suggestions? Quicksilver Dual 800, OS 9/10 (5.3.1/6.1) dual boot, 1.5 G RAM, Magma 4-slot expansion chassis.

[trakbytes]

Do you have Waves plug-ins? Waves 4.0 caused our PT 5.1.3 systems to crash on re-launch. Moving back to version 3.6 solved the problem.

rcm

[filmixer]

Yes, I do have Waves 4.0 plugins. I have Ren Maxx and Restoration. Should I go back a version of Waves Shell also? How will this affect my OS X plugins? Someone just told me going back to 5.3.1cs6 will help. Any experience with this?
Thanks.

[filmixer]

So I swithched back to PT 5.3.1cs6 and this solved my problem. I now know there is a warning on Digi's download page about this, but I think I upgraded to 5.3.1cs7 before I did the Waves 4 upgrade last year and so missed the warning. Thanks for your suggestion though trackbytes.
All the best, filmixer.