All games purchased have changed into trial versions????

You have changed of console in last days!?, i give a kick!

Because that error is comun whif people transfer their content from one console to another one new and forgot to make the transfer license...

If that is your case you have to go here in xbox.com in your profile and go in the transfer license content, follow the instructions and after finish conect whif your new console, now you will be able to use again your content (you have ALWAYS use the transfer
license tool for the system reconize the new "home" of your content).

I hope if i help you and fogive my bad english, it´s self learnerd.

Having the same issue except I'm trying to purchase the game digitally but it won't give me the option to. I only get install trial, then play trial. I've played from a disc version before and I'm past the level cap so the game prompts me every time to purchase
the full version, but again all I get is the option to play trial when I enter the Xbox games store.

That is not applicable with a trial version. The new fully purchased game will not access anything from the trial version. You can only sync your progress after purchase of the game.

It depends on the game. Not all games are available for purchase through the marketplace. You also don't necessarily need to get the trial version in order to unlock the game. If the game is available for purchase there will be an option to buy the game.

Some games have demos you can play before you buy it

Almost all arcade games have trial versions to download for free before considering purchasing them. Though, retail games don't often have all demos.