I've create a managed package and based on my question here I'm performing a check on whether My Domain feature is enabled or not. Assuming the check is implemented, I now need to let user know that My Domain is not enabled. But if I try to throw exception with custom error message everything user sees is a message about unhandled exception which looks like this The package installation failed. Please provide the following information to the publisher: *here goes my package source org ingo* Error Message: The post install script failed. So my custom error message doesn't even appear. Is there any way I can actually show it on script failure?
UPD: generally I would like to achieve something like this 
