Xbox One, Disc to Digital

The only way to get your disc game working on the "All digital" edition of the Xbox One is to purchase the game digitally.

It's not possible to "convert" a disc game to a digital game. Otherwise you could buy a disc, convert it to digital, and sell the disc to someone else who would then convert to digital, sell the disc and so on, until the whole world has the game digitally,
and only one disc was sold.

So the only way to get a digital copy of your disc based game would be to buy the game digitally again.

Specific to Xbox One, Digital allows for play without a disc present. It prohibits resale. Games purchased digitally can often times be refunded with a call to Live Support. I did this for the Xbox One version of the Destiny Digital Guardian Edition after
the news came out about the buy on 360, get it on Xbox One for free.

Disc-based games must have the disc in the console to be played. They can be resold. Disc-based games routinely go on sale unlike Digital, though MS has been better about sales on digital titles as of late.

There is no "size" difference as both digital and disc titles deposit the same bits on to the Xbox One HDD. In fact, installed-from-disc titles can be converted to digital titles (and thus obviate the need for the disc) by simply buying the digital version
of an installed-from-disc title. No re-downloading is required.

The Xbox One S console has a disc drive, so games(both physical and digital) can still be played.

https://www.xbox.com/en-us/xbox-one/consoles

The Xbox One S All Digital console does not have a disc drive, therefore it can not play physical(disc) games. As there is currently no option to transfer physical(disc) games to digital, you would have to re-purchase the digital versions.

https://www.xbox.com/en-us/xbox-one/consoles

Without being pedantic, technically speaking there is no such thing as a 'digital version' of an Xbox One game. Both the disc and the digital versions are the same. What you buy is a digital license. Of course, once you have the license you won't need
the disc.

If you borrowed your friends game on disc, installed it, then decided you also wanted this game, you just buy it from the Xbox Store. As you've already installed the game from disc you won't need to download anything, other than any updates as normal.

The Xbox 360 had separate digital and disc based games, the Xbox One does not.

What do you mean by the Xbox One does not have any digital version of games? Everything stored on the Xbox One is digital. On the non-disc based games the license is stored on the HDD while on the disc based games the license is stored on the disc.

Is the game digital or disc?

• Troubleshoot disc game issues on Xbox One for disc-based games
  
• Troubleshoot digital game issues on Xbox One for digital (downloaded) games