After logging on to the ESXI host client web ui, the Unhandled Exception dialog has started to bug me, but I think it’s fixed in a patch release since when I first installed ESXI 6.5.
This how-to doc describes the steps for updating the Host Client using the Host Client web ui itself, via Host / Manage / Packages / Install Update and pasting the URL to the current/latest .vib file which you can get from here.
The Unhandled Exception issue described here is now fixed – the specific update I installed was:
http://download3.vmware.com/software/vmw-tools/esxui/esxui-signed-7119706.vib