When I customize a default Oulook 2010 color category on my Exchange server personal mailbox, giving it a more meaningful name, the next time I start Outlook it is reset to the default description again.

For example, the default Outlook 2010 color category lables are: Blue, Green, Orange, Purple, Red. Now, if I change the blue category label from "Blue" to "Documentation," it remains that way only through my current Outlook session. The next time I startup Outlook (when I come into work next) I find it has been reset from "Documentation" to "Blue" again. Outlook will not retain my custom labels on my personal ma

Does it work for anyone?

Try restarting Outlook using the /cleancategories switch then use Upgrade to color categories.

I'm not sure what this last response means... "restart using /cleancategories"? But, this is happening to me as well, with categories resetting themselves.

Close and restart Outlook using the /cleancategories switch. This will clear the category list - then run the upgrade to color categories command to add categories back to the list.

See How to use command line switches if you don't know how to use switches.