Unselect all option for list of existing files

[CharlotteThodberg]

I often have multiple artboards within my workspace. When exporting newly added artboards, i am presented with a long list of the existing artboards with the message: "Some of the specified files already exists in the target location. The files marked below will be replaced:". 
However, the list below are so long and it takes ages to unselect all of the existing artboards individually, so i often end up with just letting Illustrator use time on replacing all of the existing artboards instead. 

In this case, it would be nice with a "select/unselect all" function.

[Monika Gause]

You are using "Export for screens"?

Can you perhaps give us some context of your workflow?