Deleting back from external drive deleted files from my computer!

Long story short, Ive set up a new computer and am in the process of swapping files from one pc to another. I backed up the original computer (ps#1) on my WD passport and attempted to restore them on the new one (pc #2). I didn’t pay enough attention and chose the option to backup pc#2 instead of restoring pc#1’s backup.
No biggie. Figured out what I did wrong and uninstalled the WD backup software so I could re-install it.
To make it easy on me (hah!) I figured I should just delete the pc#2 backup so I only had one backup to chose from when I did the restore process - So, I deleted the pc#2 restore folder from the WD Backup file folder.
Rebooted the computer, went to reinstall the software and noticed that ALL of my files that I already had on pc#2 are now gone.
I’m assuming that when I deleted the backup files it deleted the original source files as well… What went wrong? (I’m currently running some data recovery tools to try and restore what I lost - and I lost a LOT - but I’d like to prevent this from happening again.)

Hello OliversPS,

You can also try Alternate 3rd Party Data Recovery Options for the data recovery.

Refer the link provided below for more information.

https://support-en.wd.com/app/answers/detail/a_id/18754