Many times, users are either losing drives or not able to map when they log in.. happening a lot with Windows 7/2008

Cannot logon to networked drives:

Your current context is Sf.ASB
User: USERNAME Context: Sf.ASB
Your current tree is: LAW
You are attached to server GWDOMAIN.
LOGIN-LGNWNT32-430: The following drive mapping operation could not be completed.
[F:=.FS4_VOL2.SF.ASB]
The error code was 8836.
LOGIN-LGNWNT32-430: The following drive mapping operation could not be completed.
[J:=.FS4_VOL4.SF.ASB]
The error code was 8836.
LOGIN-LGNWNT32-430: The following drive mapping operation could not be completed.
[K:=.FS4_VOL4.SF.ASB]
The error code was 8836.
LOGIN-LGNWNT32-430: The following drive mapping operation could not be completed.
[L:=.FS-ATTORNEY_DATA.SF.ASB]
The error code was 8836.
LOGIN-LGNWNT32-430: The following drive mapping operation could not be completed.
[ROOT Q:=.FS-STORAGE_FED.SF.ASB:FED]
The error code was 8836.
S1: = W:. [FS4_SYS:PUBLIC \]
S2: = V:. [FS4_VOL2:DATA \]
S3: = U:. [FS4_VOL3:APPS \]
LOGIN-LGNWNT32-430: The following drive mapping operation could not be completed.
[ROOT G:=.STORAGE_USER.SF.ASB:USER\USERNAME]
The error code was 8836.
LOGIN-LGNWNT32-430: The following drive mapping operation could not be completed.
[ROOT I:=.FS4_VOL2.SF.ASB:DEPARTMENT\ISDEPT]
The error code was 8836.