Here are some potential solutions if the Toolpath add-in is not functioning or doesn't appear in Fusion.
1. Make sure that Fusion and Toolpath are both up to date
2. Check to see if an Anti-virus software or a firewall are blocking the add-in
3. Check to see if your other Fusion add-ins are working. In any Fusion workspace, go to the Utilities tab and open "Scripts and Add-ins".
4. Make sure the add-in is installed locally and NOT installed to a Onedrive or Cloud folder
5. Reinstall the ad-in How To Install the Toolpath Ad-In for Fusion