Mapped Drives not Showing

[Kaz77]

I have an issue where drives which are mapped through GPP are not always showing as available when a user logs on. It appears to be totally random as to whether the drive mapping works. The DC is server 2008 R2 and the clients are Windows 7. Any ideas on where I can look to see what is happening?

[Tesla]

try eventvwr, it should display any errors with mapping a drive, usually with an error code that may or may not be useful.