When changing the mapping of an existing persistent drive map to a DFS target, we are experiencing long delays (~10 minutes) after logging in. This is happening on all subsequent logons, so it's not a one time thing. Users are seeing a black screen (with mouse pointer) while Windows seems to be sitting there searching. After the wait, the drive mapping and everything else look normal. The drive letter is currently mapped to a regular Windows share, via GPO, and this issue happens whenever we attempt to change that GPO-based mapping to the new DFS location. Manually mapping to the new location works perfectly, but for some reason, changing the mapping wherever there is already a persistent map (either manually set or by GPO), changing the mapping seems to cause this issue. All affected clients are using Windows 7. Anyone else ever experience this?