I have an external hard drive connected to a Windows 7 (Home Edition) computer. I have another computer (with Windows 7 Ultimate), and I want to have the Windows 7 Ultimate back up to the same external hard drive, without having to disconnect and move the external hard drive from the Home Edition PC.

When I get to the "Set up backup" dialog within Windows 7, it asks me where to save the backup. I select "Save on a network". However, when I enter "\\computername\harddrivename" under Browse, the "OK" button remains grayed out. The button remains grayed out unless I also enter a Username and Password under "Network credentials". However, the account I have on the other computer doesn't have a password for it. To un-gray out the button I must enter a fake password, allowing me to click "OK", but then obviously I get a "bad password" error.

Does anyone know how to get around this problem? (Seems kind of ridiculous.) I made sure that the security settings with the external hard drive on the other computer are full access to Everyone, so permissions is not the problem. I also thought about using Homegroup instead of the regular security settings, but there is no obvious way to go about it that way, either.