When I go to SQL Server Management Studio -> Management -> Maintenance Plans -> Right click on the maintenance plan that I want to execute but the option is greyed out.

- I have checked and SQL Server Integration Services is running.
 - I can execute other maintenance plans.
 - I have even tried modifying this plan without an issue but Execute stays greyed out.
 - There is no other instance of the plan running at the moment.
 - I have also disconnected from the SQL Server and connected back but that didn't help either.
 - SQL Agent is running.
 
