Sophos Upgrade Advisor warns that Sophos NAC is detected even though it's been uninstalled

Issue

When you run the Upgrade Advisor, it warns you that you must upgrade the NAC server before upgrading Enterprise Console, even though you are no longer using Sophos NAC.

Known to apply to the following Sophos product and version
Sophos Upgrade Advisor
Sophos Simplified NAC
Enterprise Console 4.0.0
Enterprise Console 4.5.0
Enterprise Console 4.5.1
Enterprise Console 4.7.0
Enterprise Console 4.7.1
Enterprise Console 5.0.0

What to do

1. In Windows Control Panel, Add/Remove Programs (Windows 2003) or Programs and Features (Windows 2008+), look for Sophos NAC. If present, uninstall.
2. Take a backup of the SOPHOS database using the following article as a guide:
   Using backupdb.bat and restoredb.bat.
3. On the server hosting the Sophos database, open a command prompt (Start | Run | type cmd) and run the following command:
   Osql -E -S .\SOPHOS -d SOPHOS50 -Q “Delete from dbo.latestdata where DataSource=’NAC URL’”

   Note: Substitute SOPHOS4, SOPHOS45, SOPHOS47 or SOPHOS50 depending on the version of Enterprise Console you are currently using.
4. The result should say: (1 row affected)
5. Run the Sophos Upgrade Advisor again and it should now continue without stating Sophos NAC is installed.