I think you have a bad sector 0. try this: https://www.cgsecurity.org/Download_and_donate.php/testdisk-7.2-WIP.win.zip
Diskpart is a better tool for windows than disk management. It's built in. Google it
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1. Click on your start menu.
2. Type "diskpart" without the quotes. You dont need to click anywhwere after you click the start menu. Just follow the directions and type "diskpart" without the quotes.
3. It may prompt you for admin rights. Just click allow or yes
4. In the command prompt window (the black screen) type "list disk"
5. Make a note of which disk is your external drive.
6. Type "select disk 1" or whatever drive is your external drive.
7. Type "clean"
8. Type "create partition primary"
9. Type "select partition 1"
10. Type "active"
11. Type "format=ntfs quick"
12. Type "assign"
Your disk is now fixed. Format it as you please