I uninstalled the Amazon Drive on Windows 10, it left a ‘Amazon Drive’ folder in the navigation of File Explorer.
To remove this:
Always backup the registry before editing
Press Win + R, to open Run Dialog
Click View Menu and select Address Bar
Paste the following into the address bar:
Press enter to search
Double click the System.IsPinnedToNameSpaceTree, edit the value to 0
The Amazon Drive should then disappear.