I am running Zimbra 7.2.0 NE on Ubuntu 10.04 and tried to make an upgrade in preparation for upgrade to Zimbra 8. The server uses a split-dns setup.
The direct upgrade from 7.2.0 to 8 failed outright, but I do not remember the error, it left the application in a broken state, so i had to restore the whole VM from backup.
Anyway, I decided to go for 7.2.3 first, then to 8.

The only errors in the log were:
Creating server entry for <redacted>...
ERROR: account.NO_SUCH_SERVER (no such server: <redacted> )

And then while setting up the spam, ham and virus-quarantine accounts:
ERROR: account.NO_SUCH_ACCOUNT (no such account: <redacted>)

After the upgrade I was unable to log in to any of the accounts, including the admin account.

By the way, after this the upgrade to 8 was successfull, but as the accounts were lost, i had to restore from backup once more.

Any thoughts on what could be the problem?
Thank you.