Another shadow-copy creation is in progress, so the current shadow copy cannot be created. There are a number of common scenarios ...

Another shadow-copy creation is in progress, so the current shadow copy cannot be created.  There are a number
of common scenarios causing this problem:

        * If Shadow Copies of Shared Folders is set up, ensure that no two volumes have schedules that lie within five minutes 
           of each other.  
        * If automatic backup of any form is scheduled, ensure that the backup schedule does not overlap with the schedule
           used for Shadow Copies of Shared Folders.  

Generally, retrying the operation after a few minutes or changing the schedule of an automatic task should fix this problem.