I have UAC disabled on my system, and all command prompts start as elevated ("Administrator: ..."). Even if I start cmd.exe from the Start Menu, it's still elevated.
Is there a way to run a non-elevated command prompt somehow?
I need that so that I can fix a bug in some software which doesn't work properly unless running as admin.
Sysinternals to the rescue! There is an option added some time ago to run a command as a limited user.
Specifically I'm recommending running
This will run the command interactively, (so you can see the results) detached, (so the command line returns immediately -- not strictly necessary), and as a limited user.
You could remove your username from the administrator group on the computer, or create another account without admin rights.
The following command will run the program without elevation nor as a limited user. In other words, the integrity level will be medium instead of high or low.
Adding -l will run the program as a limited user (i.e. integrity level low).
As far as I know, you cannot "unelevate" a process.
If you start cmd.exe from another application (a non-elevated one), it shouldn't start as admin.