[windows] UNC path to a folder on my local computer

What's the UNC path to a folder on my local computer, and how can I access it? I have tried:

1. Security for the folder -- set to Everyone Full Control (for now!)
2. Sharing permissions -- set to Everyone Full Control (for now!)

I can see the folder in \, but can't go in ( is not accessible.)

Error message:

You might not have permission to use this network resource. Contact the administrator of this server to find out if you have access pernmissions. The network location cannot be reached. For information about network troubleshooting, see Windows Help.

My computer is not connected to a network.

On Windows, you can also use the Win32 File Namespace prefixed with \\?\ to refer to your local directories:

\\?\C:\my_dir

See this answer for description.

If you're going to access your local computer (or any computer) using UNC, you'll need to setup a share. If you haven't already setup a share, you could use the default administrative shares. Example:

\\localhost\c$\my_dir

... accesses a folder called "my_dir" via UNC on your C: drive. By default all the hard drives on your machine are shared with hidden shares like c$, d$, etc.