In Windows Vista/7, User Access Control (UAC) can cause problems when trying to add ssh keys, or use existing ones from a network location such as a shared drive.
Identify if UAC is the problem
If the server is being run as an Administrator and it is unable to see/create ssh keys, first try running the server as a non-elevated user, and see if that allows keys to be seen or created. If so, then follow the process below in order to allow both Administrator privileges to be run, and ssh keys to be used.
Configure the EnableLinkedConnections registry value.
1. Click Start, type regedit in the search box, and then press ENTER.
2. Locate and then right-click the following registry subkey:
3. Click New, and then click DWORD Value.
4. Type EnableLinkedConnections, and then press ENTER.
5. Right-click EnableLinkedConnections, and then click Modify.
6. In the Value data box, type 1, and then click OK.
7. Exit Registry Editor, and then restart the computer.
After you configure this registry value, Local Security Authority (LSA) checks whether there is another access token that is associated with the current user session if a network resource is mapped to an access token. If LSA determines that there is a linked access token, it adds the network share to the linked location.