Why do imported files have audible clicks & pops??

[SHIRK]

Finished mixing tracks for n album. Printed all files as stereo tracks in the mix sessions. Things sounded great. Now I go to master the tracks by opening up a new session (same file type, same sample rate and bit depth as mix sessions) I import (Import Audio) the stereo tracks to be mastered by copying the files into the mastering session located on the same drive. In the newly copied files there are visible and audible clicks in the waveforms. The same stereo files in the mix session do not have any audible clicks or visible spikes. It's completely frustrating. The only workaround I've found is to manually copy and rename the mix files (outside of protools using just the Mac OS finder functions) and dragging these newly renamed copies into the Audio Files folder and then Adding the files to the session. It appears to be some kind of problem in the copy function of the import audio menu. Anybody have similar problems?

I'm running PT6.9 (cs1 I believe) on a G5 DP2.5Ghz / OS10.3.8 / 2.5gigs RAM / HD3 (non accel) / 192 / Sync i/o / external FW400 drives /

[SHIRK]

Realized I'm only on 6.9 missed the update for 6.9.1 sometime back.

Will try that and see what gives.

Headaches.....