Due to licencing the national of Germany and Japan aren't playable in the standard edition of Football Manager. This guide will help you fix that!
After you have installed Football Manager on your system go to:
Program Files (x86) \ Steam \ steamapps \ common \ Football Manager 20xx \ data \ database \ db \ 20xx \ lnc \ all
Epic Games installation
Program Files (x86) \ Epic Games \ Football Manager 20xx \ data \ database \ db \ 20xx \ lnc \ all
Microsoft Game Pass
Program Files (x86) \ WindowsApps \ Football Manager 20xx \ data \ database \ db \ 20xx \ lnc \ all
/ Users / username / Library / Application Support / Steam / SteamApps / common / Football Manager 20xx / data / database / db / 20xx / lnc / all
IMPORTANT: 20XX stands for version. This can be 2020 or 2021 depending on the version of your game.
In the folder all you will see several files. Delete the following two files from the folder:
Load your save or start a new game in Football Manager. This fix is savegame compatible and will not require you to start a new save.
However, sometimes the national teams will still show fake players after the first load. At the next international squad selection this will be fixed.
With every new database SI launch, you will have to follow the steps above to make sure the German and Japan national teams keep real players.