This could happen when you use VMware Server with SMB storage or otherwise. The error message is pretty self explanatory but here is how it can happen with VMware Server.
Consider that VMware Server is installed on a machine which mounts SMB storage location with an administrator account. Windows doesnt allow two sessions access the shared storage from the same machine. So if you are logged in VMware Server machine and is viewing the files of the shared folder(which is mounted on it), it means that you are causing issues for the other connection(maybe a program that uses it). So as indicated by the message, you need to kill all the sessions and allow restart the program.
1) Look at the sessions that are simultaneously running. On a Windows machine, Run -> ‘net use’. This will list all the connections.
2) Delete all the connections to the storage. Better still, do a ‘net use * /delete’
3) Ensure that you dont access the shared drive when the program is running.(to avoid starting a new connection)
It should work now.