Hi KevinMO,
I was able to reproduce this crash on my system running UE4.11.1 and have entered the following bug report: JIRA [UE-29453]. I noticed, however, before uninstalling the Substance Plugin, it was labeled “4.11.0” so it may just be a matter of Substance updating their plugin.
In the meantime, uninstalling the Plugin will allow you to run UE4.11.1. Let me know if this does not resolve your issue.
Thanks,
.