We have found that if you are using Discord it can cause a crash. This is because Discord appears to be attempting to force an overlay for Wizard101 that is in conflict with the game.
Try this as a workaround for the time being. To turn off the overlay follow these steps:
1 - Go to Discord 2 - Open up your User settings
3 - Click the Overlay tab and disable it.
If this does not resolve it for you we recommend not using Discord for the time being while playing Wizard101. Please also keep in mind that KingsIsle does not officially endorse the use of Discord, and we do not manage or run our own channels on the platform.