Here I am using Windows 10 PRO, version 1703, build 15063.138 and mIRC is opening normally with version 7.48.
I recommend you do a clean boot of Windows, to determine if any program is causing conflict and generating this error.
A friend who was having problems with certain programs after updating Windows, and the cause of the problem was an incompatibility of the version he was using from Riva Tunner Statistics Server.
I think it's safe to say that those of us running Insiders have tried rebooting...
I for one have a minimal level of additional services and applications running, and none that have changed between it working and not working.
