Once SharePoint Online is mapped to the LinkFixer Advaced server, you could browse your files using File Explorer and you could also browse the files using LinkFixer Advanced but we're not done yet.
The last thing that you need to do is Authenticate SharePoint Online in LinkFixer Advanced.
1. Open LinkFixer Advanced and go to Network Locations under Home Tab
2. Double click row of you mapped SharePoint Online. Type in your email address and password and hit Test button.
Note: You need to use the same login credential when logging in to your Internet Explorer and mapping SharePoint Online drive. Failed to do so will end up getting issues and you will need to start the processing again.
3. Hit OK button one the test is succeeded and hit OK again to exit the Authentication window.
4. You could start running LinkFixer Advanced processes on the SharePoint Online mapped drive is Online and fields are not blank.