Retain 4.9.0.1 stuck in maintenance mode after upgrade

After upgrading to Retain 4.9.0.1, when attempting to log into the Admin Console, will see the  message  "performing routine maintenance" on the screen instead.

In the RetainServer log, the following error message can be found:

The following errors were detected during a check of the configuration database schema: Wrong column type in Retain.dbo.t_sql for column f_searchphrase. Found: nvarchar, expected: varchar(4000)
Retain will be switched to maintenance mode.