I bought the Master Chief collection digitally, however my Xbox has now died on me and I am getting a new one under warranty tomorrow. Since moving house my internet is utterly disgusting and will likely take me a few days to redownload the game (60GB)

Can I go buy the disc version, install it that way, and then return the disc version and the system will play it fine?

I believe a game installed by disc can be converted into a digital copy of the game if you buy (or re download in your case) it from the marketplace afterwards. I have no experience in doing this myself so please don't take my word as gospel on this, but I remember hearing a bit about this when the Xbox One first came out.

Don't rebuy it. I'm 99.9% sure any digital games associated with your gamertag will be available for re-download once you sign in on the new xbox and make it your "home" xbox. I'm also 99.9% sure that games installed from a disc require that disc to play them. And who lets you return opened disc games these days anyway? I know the download times suck, but just start it before you go to bed tonight and if it takes a day or two, do something else until it's done.

I work in a game store where I can borrow the disc, but if itll associate it with the disc not the digital its not worth it

I believe that if you install a game via disc then purchase the digital copy you do not need to redownload the game like on PS4 rather can just use the digital copy of the game straight away without the disc - so I think what you were originally asking is correct.

I can't say for certain but I rented Mordor once and when I took it back but didn't uninstall it, launching it prompted the Xbox to tell me I needed to insert the disc or buy it digitally on the Xbox store... Don't know if that means it would unlock because I didn't buy it but I think it's worth a shot.

Just an FYI though, you'll still need to download a pretty big update after that though.

I installed Titan Fall from disc and then got the digital version free from a give away, the game converted to digital with no issues.

If you install a game via a disc and then get the digital version it will allow you to play.

However, for Halo you have to download a whole bunch of patches anyway so the amount of time you'd save wouldn't be as great as most games.

The patch is 20GB or so if I remember rightly, which whilst is still going to suck for my internet, better than the alternative 60GB. Put thanks for the input guys, I'll grab a disc :D