Hi Arthur,
The information about how to use Track Transfer in this situation is in the Late Breaking Technical Information under the "Track Transfer" heading at
http://www.digidesign.com/serv/hotis...#tracktransfer
Please list your whole configuration, including RAM, OS, cards, Disk Cache, Memory settings, etc. so we can see if any of those might be factors. I have opened lots of 4.3.1 sessions in 5.0 on a 9600/350/256kRAM MIXplus system with no problems running both OS 8.6 and 9.0.
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Bruce Paine
eMarketing