How to Fix the Steam DLC Crash
The developers are officially investigating why the Steam version creates stability issues right after the DLC installation. While a permanent hotfix is likely being coded right now, they have provided a temporary workaround that seems to work for most users.
The Solution: Simply restart your PC.
It sounds like the classic "turn it off and on again" IT support cliché, but in this case, it is likely necessary to refresh Steam's file verification or clear out temporary cache conflicts caused by the new asset integration. If you are stuck on a crash loop at the launcher, a full system reboot is your best bet until a patch lands.
Which Content Is Affected?
This issue is specifically targeting the Steam version of the game following the installation of the Additional Digimon & Episode Pack 1: Alternate Dimension. If you are playing on PlayStation 5 or Xbox Series X|S, these reports do not currently apply to your platforms.
The team has not given a specific timeline for a permanent patch, but given that this blocks access to paid content, you can expect a hotfix to be prioritized. For now, a quick reboot should let you get back to exploring the Digital World.
Soren