I resized my partition to increase my bootcamp drive few months ago on Disk Utility on Mac and after that I decieded to have more space on Bootcamp partition so I resized it again by set new size for Macintash HD but when I reboot my Mac and hold alt key there was no Windows option so I googled and followed this discussion: https://discussions.apple.com/thread/4144252 based on this answer: https://discussions.apple.com/thread/4144252#19071422, after I rebooted my Mac I saw Windows option but after select windows I get System Operating Missing. here is current situation of my partions and disk: gpt show: disk0: mediasize=500107862016; sectorsize=512; blocks=976773168 gpt show: disk0: Suspicious MBR at sector 0 gpt show: disk0: Pri GPT at sector 1 gpt show: disk0: Sec GPT at sector 976773167 start size index contents 0 1 MBR 1 1 Pri GPT header 2 32 Pri GPT table 34 6 40 409600 1 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B 409640 850647624 2 GPT part - 48465300-0000-11AA-AA11-00306543ECAC 851057264 1269536 3 GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC 852326800 84899440 937226240 39546880 4 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7 976773120 15 976773135 32 Sec GPT table 976773167 1 Sec GPT header