Originally Posted by: GrazRacer 
Here's what I can say.
In the marketplace, where you can buy the treasure map, the map is shown as "purchased" already but I don't have anyway to install or verify that it has properly installed.
Any suggestions?
Go to the Xbox Store and verify.
On the dashboard highlight Forza Horizon 2.
In the menu select "View in Game Hub"
Once the game hub opens select the option to "View in Store"
Once you have the store open scroll over to "Add-Ons" and select the 3 dots to view more.
Scroll along until you find the treasure map and select it.
If it is installed it will show "INSTALLED" in the top right. If it shows "INSTALL" it's purchased but not downloaded.
Also, there are only 10 barn finds on the mainland and 1 on storm island. If you have already found them all then the barn find map won't have anything to show.