Unable to mount Seagate external again with 10.10.5 Update

I have a 2 month old new 15" 2.8 Macbook Pro and had to add an NTFS driver to get my Seagate USB 3.0 Backup Plus External 5tb drive to mount properly (it just quit mounting one day) with Yosemite. It worked fine on 10.10.4 until the 10.10.5 update last week and the drive will not mount again even with a different type of NTFS driver installed. I have rebooted, restarted, powered up the drive differently and tried two different drivers now.

Any help on getting the laptop to see this drive again? Drive still mounts fine on my older laptop running Mountain Lion.

Thanks!