When I try to start Windows Live Mail an error messages appears on the screen which says:

"Windows Mail could not be started. The application was unable to open the Windows Live Mail message store. Your Windows Live Mail mailbox data is currently being used by another program, such as a virus scanner. Close the program or wait for it to complete its operation, then open Windows Live Mail again. (0x800C0155)

I'm not aware that my virus scanner is doing anything different from before and having waited a significant amount of time (to allow it to finish) I still can't start Live Mail. 

Can you advise me as to what this issue might be and how to resolve it please?

Thanks