I believe this error started happening because we moved the “wait for NE build” to the background build thread instead of blocking the UI. It used to happen as part of launching/rebooting.
Not sure I follow all the cases you’ve presented but from reading the code it seems that if we get that i/o exception while trying to delete the .exe of the already running dmengine, we fail to report it to the user and also won’t attempt to launch or reboot the running dmengine.