The problem probably is that for some reason Windows PC does not allow XO to copy the local (offline) database with the map tiles.
When you start XO the first time it copies this offline map database to “C:\Users\XXXXXX\AppData\Local\GMap.NET\TileDBv5\en”, where XXXXXX is your Windows user name. You will have to select “show hidden files” in the Windows explorer to see it.
This is the database file:
In the XoData folder there is also a database file:
Please copy this file to the TileDBv5/en folder above and rename it to Data.gmdb -> you can delete or overwrite if there is already a file with that name.
If you now start XO the map should be shown normally.