Sophos Control Center: reports 'No scheduled downloads'

Issue
The status-bar of Sophos Control Center reports 'No scheduled downloads'. Manual updates work, but automatic updates fail.

One or more of the following is seen:

• EM Library event log shows warning messages about No configured download scheduled
• In the message log of EM library the error message is present, There are no current active schedules set

Sophos product and version 
Sophos Control Center, version 2

Technical information
The C:\Program Files\Sophos\SCC\Ssdata.idx has become corrupted. You must delete it then re-create it.

What to do

1. In the Control Centre, select 'Action'|'Configure updating'.
2. Turn off the automatic download schedule.
3. Delete C:\Program Files\Sophos\SCC\Ssdata.idx
4. In Windows Services, restart the 'Sophos Enterprise Manager Scheduler' service.
5. The C:\Program Files\Sophos\SCC\Ssdata.idx should be recreated.
6. Tick the box for automatic updating, the status bar now indicates the next scheduled download time