Mapped drive for Microsoft SQL Server 2008 I've noticed strange issue after this weekend. Maybe someone could explain this situation.
I've got SQL Server 2008 placed on Windows Server 2008 with read/write permission to catalog ( let say Workgroup ) on network drive ( it is used to make backups )

To make catalog Workgroup visible for SQL Server, I've used this syntax:

  xp_cmdshell 'net use Y: \\network-disk-server\Workgroup [password here] /[user here] /persistent:no'


And everything was fine. I could make backups on Workgroup. But after Sunday SQL Server 2008 couldn't see mapped drive anymore. After making net use syntax again, I get error:


  Multiple connections to a server or shared resource by the same user, using more than one user name, are not allowed. Disconnect all previous connections to the server or shared resource and try again.


So I think that this mapped drive still exists, but somehow it is not seen by SQL Server anymore.

I am using Domain user service with read/write permissions to workgroup folder and sysadmin fixed role on MSSQL.
I've got explanation ( tricky ). Maybe someone could get use of it:

Administrator might set maximum number of connections from one account to external resources ( in this example - drive ). When the number of connections is reached, You don't have access to it ( and from SSMS it is not visible ).

Recommendation:

Check, using for example sp_who, do You have any sleeping processes on Database Engine Service Account. That requests could hang on external resources, and block access for other requests.