Halo Masterchief Collection suddenly has problems with video and audio

I noticed today that my hdr brightness in settings had reset to the lowest value.

check this to see if its happened to you.

Thanks i will try this but will have to wait till the weekend because installing takes so long.

I still wonder how this could happen and whether this has anything to do with another game or the Halo reach installation or an update.

Ok, thank you. So go ahead and uninstall the game and then power cycle your console. Simply use the restart command at the bottom of the System menu in your guide or hold the Xbox button and it is one of the options there as well. Once you console is back
on you can then reinstall it. When you go to play your game save file will be resynced to your console.

You won't listen your saved game by uninstalling and then reinstalling. Game save data is stored in the cloud and will be resynced when you play it using your account. You didn't say whether this was on Xbox One or PC. This would be helpful to know in
order to continue to assist you in troubleshooting the problem.

that‘s it。 thank you’