Each group has a unique identifier in addition to its name. Deleting a group deletes this identifier and it cannot be restored, ...

Each group has a unique identifier in addition to its name. Deleting a group deletes this identifier and it cannot be restored, even if you create a new group with an identical group name. This can prevent members of the deleted group from accessing resources they currently have permission to access. 

Are you sure you want to delete the group %1?