So I have my computer dual booted with max os Yosemite and Windows 8.1. Today I decided to increase my windows partition. (bad idea I know) I used windows disk manager to do it, and the process went smoothly. Or so I thought. Starting my computer up in windows has no problems, but when I hold the alt/option key to select Mac OS X It wont appear, but the Mac recovery partition does. So I use the recovery partition to open Disk Utility and it says that the partition that mac is installed to is ms dos, but in windows Disk manager it says it is HFS just like the recovery partition. So my question is, why does mac think it is ms dos and how do I make it bootable again without losing Windows? I also don't want to resort to re installing mac osx and losing all my stuff.