Passport SE 1TB drive not recognized in mac, but is in disk until

I bought a passport SE 1 TB and installed the drive on my mac about a week ago.  It has worked well as my drive for time machine.  Today, time machine sent a popup that said that it could not find the passport drive.  I looked in finder and saw this to be true.  I tried using disk util and was able to bring the drive up in the utility and both verified and repaired the drive.  Both said the drive was okay.  I don’t understand how disk util can see it but my mac cannot. Odd.

I tried connecting the drive to a windows xp machine and it  recognized the drive and loaded the needed software. Once the software was loaded I could not find the passport drive in windows explorer.  Hmmm likely a problem with the drive?

Should I reformat and see if that helps?  1 week of backups is not going to be such a big deal but I hate to reformat if I don’t need to.  Anyone have any ideas about what to do with this?  Should I just contact WD support and try and get a replacement?

Any help will be much appreciated.  Thanks

If the drive has been working with your Mac then Windows will not see the drive since Windows does not recognize the HFS+ file system.

I’d reformat the drive on the Mac and then a firmware update.

Thanks for your response.