My Passport Ultra: backed up all my files from old PC, now won't download to new PC

I backed up all my files from my old Assus PC onto My Passport Ultra (external drive).
Have never had a problem accessing anything on this device.
Now I have a new PC (Lenovo) and am unable to transfer files…getting message that disc needs to be formatted.
Device is recognized on the device Control Panel.
HELP!!!

HelloP,

Please follow the troubleshooting steps mentioned in the below link:

If troubleshooting steps don’t resolve the issue, You can download and install data recovery software’s from the below link:

Once the data is recovered you can format the drive and use it once again.