Because game saves are tied to specific Xbox User IDs (XUID), you cannot simply drop a file into a folder and expect it to work. You must use a "Save Swap" method. The most reliable links for these files and tools are found in specialized communities:
For the Microsoft Store version, the standard installation procedure for a downloaded save file involves: forza horizon 5 100 save game microsoft store link
While there isn't a direct "Microsoft Store" button to download a save, you need to find a community-provided 100% file that works with the MS Store version. Because game saves are tied to specific Xbox
Using a 100% save file, especially one obtained from third parties, carries risks. Using a 100% save file, especially one obtained
Copy the full name of this large file and save it for later.
Look for save files on well-known game modding forums and communities where users can rate and comment on the files. Communities like the forzamods Discord server are often the most reliable sources. Websites like VG Times and SaveGame.info are also common destinations, but always exercise caution. Avoid sites with intrusive ads or that require you to complete surveys before downloading.
A note on achievements: using a 100% save file can affect them. You may receive achievements for progress you didn't earn yourself, possibly diminishing the satisfaction of unlocking them. While some players report achievements still function with modded saves, it is not guaranteed. For achievement hunters, it may be best to use a 100% save on a separate account.