mail won't sync on MBA, Weird

My iphone and ipad sync mail perfectly but not my Macbook Air.

while in icloud pref pane everything is checked off but when I click 'show all' and then click back to icloud 'mail' is unchecked. Happens every time.

Been searching around a bit and haven't found others with this problem yet. All I've tried is quiting mail and restarting computer, no joy. Thanks for any help.

2GHz Intel Core i7, 8gb ram, OSX 10.7.5, Mail ver 5.3