Backup Status Overlays Not Working

I have a Toshiba Satellite Prop laptop running Windows Vista Business 32 Bit.

Yesterday, I upgraded my Norton 360 programme from v.3 to v.4.

At first glance everything looked fine but I then spotted that the Backup Status Overlay icons - both the green ticks (denoting backed-up) and the blue 'double-arrows' (denoting not backed-up) had disappeared from all my files.

Even though my last full backup under v.3 was only a day old I conducted a fresh back-up in case it was a case of changing from one version to another, but still no overlays appearred.

I then deleted all my back-ups and started from scratch as if no back-ups had ever been done before.  Once again, nothing.

I'm assuming that the back-up was successful as my external HDD is showing the correct N360 back-up folder and the correct GBs of back-up folder size.  So why are the overlays not showing?

Does v.4 have a compatibility problem that wasn't present in v.3?

If someone could help me get these overlays back I would be most grateful as they were a useful aide memoire to what needed to be done.

And by the way, the Backup Status Overlay check-box is indeed shown as 'checked' in the Settings/Quick Controls list.

Thanks,

Ian