I don't have a tutorial up about OS upgrade install, but there is good one
Here
and a new one recently posted by ct5694
Here.
This is a known issue on OS 4.5 install/upgrades and it is recommended to remove it prior to the upgrade, as many have reported rebooting issues and problems with loading media.
If you don't experience any issues you should be fine, but if you do start having issues, more than likely that is going to be why.
And yes, you can reformat the card as well.