Following a discussion on Slack, I thought it might be a good idea to start a thread where people can let us know if they migrated to CP and their site broke.
They could let us know what happened and whether it was an incompatibility with one or more plugins or something else.
Still, if you do have a site that broke as a result of switching to ClassicPress, please provide any of the following that you can get your hands on, so we can see the issue and fix it: