Time Machine will not make a new backup. A red "i" does not appear.
I am running Time Machine and I am using a Drobo as an external hard drove where the backup is stored. When I select "Back Up Now" from the Time Machine menu, the Time Machine Prefrences window first displays "Scanning XXX items...." followed by "Preparing XXX items..." After that Time Machine Prefrences displays the date of the Latest Backup, which was 6 months ago.
Any help would be greatly appreciated. I would like to upgrade my mac soon, but I do not want to do so with a proper backup in place.
Mac mini, Mac OS X (10.6.8)