I recently had to reformat my USB 3 drive to ExFAT for accessing it properly on Mac for Backup. Everything was fine as long as I used it on Mac and Windows. Once I have lost access to Mac and shifted to my favorite Ubuntu machine I was surprised by having similar issue that I had on Mac but with ExFAT this time. After searching a bit I found that ExFAT partition type isn't supported out-of-box. To enable this one need to add the support separately.
Here is what is needed to enable ExFAT support.
$sudo -s
$apt-add-repository ppa:relan/exfat
$apt-get update
$apt-get install fuse-exfat
This will install the ExFat support and the drive got mounted automatically.
In case you want to mount the drive manually you can do something like:
mount -t exfat /dev/sdb1 /media/exfatdir