Yes, but once you've selected the items to change don't you then have to click the "Check" or "Uncheck" buttons, which doubles the time? I was suggesting that clicking on a checkbox and then dragging across others would change the state of all of them, without having to click on a separate button.

This isn't the usual behavior of checkboxes (you have to both click and release on the same checkbox to affect anything), but given that there are so many checkboxes and they're all the same it makes sense in this situation.

You can do that. Just make sure you start dragging in the "Name" column, but outsize the filename (in the blank space).

You can also click on the first file and than Shift-click on the last.

If you want to uncheck (or check) a number of adjacent transfer checkboxes in the "Synchronization checklist" window, you either have to individually click on the checkboxes, or select them and then click "Check"/"Uncheck". If you click and hold on one checkbox, and then drag through some others, only the first one gets checked.

Suggestion: once you click and hold in a checkbox, have every checkbox you drag across change state. This would make it much quicker to change the state of small groups of checkboxes.