This happens from time to time, even with folders created months ago and
haven't touched...

I right click and select "Rename"
Type in a new name and hit enter
An dialogue pops up with the title "Destination Folder Access Denied" and
says "You need to confirm this operation" with one "Continue" button showing
the admin/security shield icon.
I click "Continue" and go to the greyed-out screen with the "User Access
Control" dialogue box.
I click "Continue" again, and I go back to the "Destination Folder Access
Denied" dialogue, which now says "You need permission to perform this action."

Obviously this is very frustrating (and a little scary), since I created all
of the folders this is happening with. There is only one account on my
machine, and I am the admin.

Usually, if I restart the machine I can go ahead with the renaming (or
deleting).