Explorer Locks Up When Trying to Share

If I click on 'Share' on the sharing tab of a folder's properties, I get the 'File Sharing' dialog with a 'Share' button at the bottom. Clicking this leads to a progress bar saying it's sharing things and may take a few minutes. 20 minutes later, still no movement.

Clicking on 'Advanced Sharing...' on the sharing tab of a folder's properties, the button gets stuck in the depressed state, no dialog pops up, no buttons are clickable on the properties dialog, and I enter a depressed state.

What folder are you trying to share?

Just a folder.

I tried a different folder on a different drive, same thing happens.

Are there lots of folders and files within the folder you want to share? The more there are, the slower it will be to set up sharing, because Windows sets up sharing on each item within the folder you want to share, which means each item within each subfolder.