Capcom has issued a stern warning of a “serious bug” affecting Marvel vs Capcom: Infinite save data, related to the update which went live recently. The bug only affects Xbox One users, and only those using disc versions, so digital downloads of the game seem to be in the clear.
According to a recent Capcom blog post, the bug is only a problem under a “specific rare circumstance”, but will surely be terribly annoying for anyone encounters it. The bottom line right now, before we get into the details, is do not create new save data right now.
I’m going to lay it out for you just as Capcom has, lest I should make a mistake and you lose all your data and try to sue NAG.
“The only situation where you will encounter this bug is if you have updated the game and have save data from the latest update, but later uninstall the game then reinstall from disc and attempt to use the save data without having applied the update. The updated save data and older game will be recognized as not compatible and the game may prompt you to create new save data as it may read the existing data as corrupt.”
There’s no fix right now either, so the only way around it is to “make sure you exit out and apply the latest update before you play the game. This will then ensure your save data stays intact and will work properly”.