The following error appears when you try to start "Web Management Service" in Plesk->Tools & Settings > Services Management :
Error: Could not complete the operation: defpackagemng failed: The service cannot accept control messages at this time. (Error code 1061) at ControlService 'WMSVC' with code 1
WMSVC (IIS Web Management Service) is stucked or is in the stopping status.
Find the process with Image name WMSvc.exe in Task Manager and kill the process.
Try to start IS Web Management Service once again.