Greyed out external exFat drive, can't access

hi everyone,

I've just got a brand new Macbook Pro 13" early 2015 model. I've been using Windows and Gnu/linux myself until now but have used Macs in the workplace multiple times, so I do sort of know what I’m doing. I know that NTFS and NFS+ both are file systems that Apple and Microsoft, for whatever stupid reason, do not support in either operating system. So I've formatted my external harddrive (USB 3.0, no external power, 1TB, Toshiba) in ExFat because this format supposedly would work with both OS. It works fine in Windows 8.1, which I've also used to format the drive. Now here's what happens when I plug the HDD into my Macbook USB 3 port:

1. plug in drive to USB 3 port on the right side on the macbook
2. drive icon quickly pops up in finder, goes away after 2 sec.
3. check the Disk Utility app. I find the drive, but the partition is greyed out, not mounted.
4. Try to verify the disk through Disk Utility gives me no errors. Should be fine, but still not able to mount.
5. Go online and ask the community for help. Hope for answers J

Here's some screenshots of the Disk Util.

http://i.imgur.com/IyzRacw.png

http://i.imgur.com/6CdwBUE.png

Any help would be greatly appreciated. There might be more apps to debug the problem that I am not aware of. I thought that there was a fstab file in /etc/ but no, nothings there.