My game cant upload because it always stops and says to resume the loading so what can I do?

Hi and thanks for reaching Microsoft Xbox gamer's community. My name is Josef.
I'm an Independent Advisor and a Microsoft Xbox user like you.

Hope you're doing great today despite this MARTINEAU

Additional information is needed, please answer the following questions to assist you properly:

Is this happening on Xbox?
If yes, what console do you have?
Please share an screenshot or video of the problem to understand it better (don't forget to conceal personal information is needed)
Is this happening once you try to open the game or inside the game itself?

And what did you tried so far to fix this problem
In that way I can advise you different things or how to proceed

I had the syncing thing when I was playing Starfield on my Xbox and ROG Ally, weirdly it was always when going from my Ally to my Xbox, not the other way around.

I eventually worked out what the issue was, I was switching off the Ally as soon as I stopped playing. What's I should have done was leave the Ally on for half an hour or so while it uploaded the save file to the cloud..

Perhaps that's the issue with you, the game knows there is an updated file, but cant access it because it wasn't uploaded fully. Perhaps turn on your old PC and let the save file upload.

it always says "Installation Stopped" and when i press "Resume Installation" it tries and boots up for about 10 seconds and then stops again with the "Installation Stopped" message popping back up

and when finally stop load it says that it cant do it at this moment

Hello i have the same problem here but none of this helped me. When i start the game and try to go to online it load for a while and just says check your connection but everything is alright on my side this means there is something wrong on Microsofts end.

I hope they'll fix it soon because i really want to play with my friends.

Do you play on a Xbox Series X|S console?

If so be sure to close the game properly by opening the Xbox Guide (Xbox button on controller) > Forza Horizon 5 > More options (Menu button with three lines) > Quit.

This will close without saving the game to Quick Resume which is known to cause connection issues with online games.

You can also see if it is in Quick Resume when you start the game and it says Quick Resume in the top right corner on the game's splash screen, or by checking the Quick Resume group when you open the Xbox Guide > My games & apps > Quick Resume.