DCPP: upgrading from 3.8 to 3.9

to upgrade:
-decrypt all volumes
-deinstall version 3.8
-install version 3.9

I successfully decrypted one volume, but on the system one i got:
---------------------------
Extra compatibility info
Failed on Call Device Driver 2 DISK_INFO
OK
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any clue ? seems to me a bit "dangerous" to deinstall before decrypting all volume.

ps: i am on Vista RTM