You are getting lots of information. This is actually a simple thing to do and nobody is born knowing how to do it.
First; are you using a MAC (or apple) style computer and running windows beside the MAC OS? If it is a MAC there will be a picture of an apple with a bite out of it on the outside of the cover.
You had said you upgraded to Windows 10 from Windows 8.1 so I assumed you were using a non-MAC computer.
Do not mess with Linux no matter what anyone else says. Linux is great but you do not need to learn something big and complicated to do what you want to do.
Basically you will want to delete the partition (or all of them if there are more than one) on your Passport drive and then format it again so you have the use of all of the drive without any WD software.
After you do that your Passport will work in any Windows computer.
There are various youtube videos for ‘delete partition and reformat’ but I recommend you get someone local to you to prepare your passport. It needs to be done on Windows (if you are using a Windows computer). Make sure you have done the first step of copying all of the data off of it before doing the partition and reformat.
It is 2 minutes of work and easy to do if you know how. It is fraught with agonizing decisions if you do not know how to do it.
Give someone $20 or find a friend.
Make sure you have done the first step of copying all of the data off of it before doing the partition and reformat.
Sorry, this should have been first in the list of things.
On your computer open ‘file Explorer’ and make a folder called ‘Passport Copy’ on your ‘C:’ drive. It might be called Windows_OS or some other name in front of the drive letter.
Then plug in your Passport and wait until it opens a window. If it doesn’t automatically open a window you can find it in ‘File Explorer’. Right-click on it and choose ‘open in a new window’.
Select all of the data (it all turns blue). If you select a folder all the data in the folder will come too so you do not have to select the files in a folder individually.
Right-click on the blue and select ‘copy’
Now open the new folder you just made called Passport Copy. Right-click inside the folder and choose paste. All of the data will copy over from the WD passport drive into the Passport Copy folder.
Now you are safe to reformat the WD USB drive. See above.