To close activity by mass injection

Hello

You can use the multiple update function in the toolbar of the list area(v9.0).
Launch the feature, a new screen is displayed.
On the line "change status to ..." choose closed
Save

Your activities are now closed.

Be careful, however, if your workflow has controls to be carried out! If a field becomes mandatory to move to another state, such as the result field to be completed, then these activities will not go into the closed state ! 

Enjoy !