Started losing data and then computer wouldn't boot up

I noticed a couple of days ago that when I tried to retrieve data from my Passport that older files were blank. I turned off the computer thinking a re-boot might help but the next morning it was the same. The only data I could access was the most recent uploads on the drive. Today my iMac wouldn’t boot up at all until I unplugged the Passport.
I also have the High Sierra 10.13.4 update. Could that be the cause? Will I be able to get my data back?

Hi Ken3,

Maybe you should try contacting WD’s Technical Support about this.

To Contact WD for Technical Support
https://support.wdc.com/support/case.aspx?lang=en
The link below will allow you to call support.