Thomas wrote:
WinUAE has to be run as administrator for direct harddisk access. On WinXP is is sufficient to have an administrator account. On Vista you have to right-click the icon and choose "run as administrator". Or change the shortcut's properties to always run as administrator.
Thanks for the information. I set WinUAE (and AMiKit) to run as administrator, and the button activates. Unfortunately, the external HD does not appear in the resulting dropdown list. I'm guessing the drive has to be internal.