External Hard Drive is not recognized on new Mac

[Nicholas1501]

I upgraded to a new Mac and my external Hard Drive is not recognized. It is ExFAT Formatted. Ive checked Disk Utility and Finder, it simply does not recognize the external hard drive whatsoever. Ive been trying to change the permissions on the external drive using my mid 2010 macbook pro (OS high sierra), but the info window does not allow changes to permissions (no lock icon). it currently says "you have custom access".
Also, the dates are incorrect.
Created: December 31, 1969
and yes my computer date is current and correct.

THX

 

[ght56]

Do you have access to a Windows 10 computer? There is a very good chance that this has to do with ExFAT being extremely prone to corruption--this can happen especially easily if the drive is force ejected or disconnected without being properly ejected, afterwards the drive will spin up but the disk will not be recognized. For whatever reason, Windows is better at repairing this than Mac, and as soon as you plug it into the Windows system it will likely notify you that there is an issue and offer to repair it. If not, the Windows ChkDsk/f/r command may be able to repair it.

Someone else may have suggestions on how to repair this on macOS but I have not personally had luck using Mac to fix ExFAT drives if you are indeed in the situation I think you might be in.