A:\ Drive access permissions

I am using a Windows NT 4.0 Workstation with SP6a loaded on it and after a fresh boot the first time I try to read the ‘A’ drive I get a permissions error saying you do not have rights to the folder.

“You do not have access to the folder A:\. Seeyour administrator for access to this folder.”

Subsequent attempts to access the drive are OK. I have checked everywhere and have been unable to find a solution. Does anyone know what can be done to solve this issue?