How to transfer ALL Garmin BaseCamp data from old computer to new computer

I started using basecamp on my new computer, and have created  new saved GPS data in Basecamp on the new computer. Unfortunately, when exporting the backup data from the old computer, all the new info I created in Basecamp in the new computer will be erased. SO I will have to figure out some other way. The backup is in one file that is not splittable--so I can't pick and chose which folders I want to import into my new computer. I need someway to chose which folders to import to the new computer so I don't lose the new GPS info I have saved since I migrated from the old computer.

Export the new data as a .gpx file or files. Import your old database then import the .gpx file into a folder you've created within the old database than you've now imported.

Be careful when using Backup/Restore with Basecamp on Mac.  Some of the data in Tracks can be lost in the Backup/Restore process.  I sent Garmin several files showing the issue and they acknowledged it was an issue but the answer was it works on Windows so use a Windows machine.  Garmin apparently does not care about data loss if you are using a Mac.

I don't use Backup any more but just make a copy of my BCLIBRARY file as a backup.  I created and use my own BCLIBRARY file instead of using the hidden one Basecamp defaults to.  It makes it a lot easier to find and manage.

I am copying each list folder from the old computer and am importing it into Base Camp on the new computer. after typing in the folder names. I have noticed that all list folders on the old computer that had only waypoints in them are now empty. When I get everything transferred to the new computer, I will do a backup on the old computer from a previous version of Base Camp and hopefully the waypoints that are now missing will be restored. Any thoughts on why the list folders with waypoints would have their contents erased?