Link Repair v3.x.x.x
Due to the way Microsoft UAC works it is possible for mapped drives to not appear when running an application as Administrator.
Within Explorer disconnect the mapped drive by right clicking the drive and select disconnect.
Start an elevated command prompt (use run as Administrator on c:\Windows\System32\cmd.exe) and map the drive using net use. E.g. net use Z: \\ServerName\ShareName
As the drive has been mapped within an elevated command prompt it should now appear in the selection list. If Link Repair is open then you will need to click the refresh button (green arrows) in the top left of the selection list pane.
A work around is to temporarily disable UAC in Control Panel\Users Accounts (requires a restart). Note: This method should only be chosen if all the files Link Repair will be opening are trusted and malware free as switching UAC off lowers security. If this method is chosen then UAC should be re-enabled as soon as Link Repair is finished.