Options: 1. Remove the post-build event
Fix the commands defined in the post-build event
Fix the underlying problem that's preventing the commands from working
Ignore the failures?
It's not clear why you can't edit the post-build event. You can't find where in the UI to edit it? These are unfortunately different depending on the type of project you're working on. I think we'll need more information (like what you've tried) in order to provide more help.