Hi -
In addition to what Randy mentioned, you can confirm what service accounts are already being used. Go to Computer Management and select Services. Double click on the AvDSAD service and click on the Log On tab. Repeat for the AvMsgMonitorStore service. These services use the unitydirsvc account and unitymsgstoresvc account respectively. Another place to check is on the Unity server, local Users and Groups, group Administrators. These accounts will also be included here. The unityinstall account is typically used for installs, upgrades, etc. but if you are performing an upgrade you will be prompted for the accounts and passwords to be entered. Note: If you don't know the passwords associated with the Unity accounts, you can change the passwords, however, you will need to rerun both the Services configuration wizard and the Message Store Configuration wizard to get Unity operational again. I've done it and its easy to do - use the Unity reconfiguration guide and work with your Exchange admin if need be. You might consider doing this change on a separate weekend just to get the accounts working and known, before making such a change on the same weekend as upgrading to 5.X.
Ginger
