TK1468

Hi guys and girls, I have had arma 3 for say two weeks now and got two bundles and the base game, and have played a few hours (125Hrs) and came home today to have alittle bit of fun, and found that i had to redownload the whole game again, can someone please explain to me why, who and what the heck is going on,considering i have played on official servers,and also have done most of the prologe. Very confused player here,and would love to here any genuin input you may have. Thank you