I tried changing the DelayValidation to True but it did not work so I tested updating Visual Studio, but no. Then I came over this issue: https://developercommunity.visualstudio.com/t/ssis-crashing-on-dataflow-open/415794 So I tested to move the Visual Studio window from the external screen to the laptop screen and it worked at once and continued to work even when I moved it back to the external screen! Then I tried to set DelayValidation to False again, and it stopped working. So I would say that setting DelayValidation to True really is the way to go, but sometimes, if you use an external monitor with a laptop, you have to move Visual Studio to the laptop screen.