Based on your original report, this issue is related to saving the windows maximized position?
It's just that no matter what I do, I can't get mIRC to open the channel maximized. This is a different machine, at home I've been using mIRC for 20 years with maximized channel without any problem. I'll make a video out of it. When I set this new machine up, the screen display was not aligned correctly, aka maximized windows (not just mIRC) xy position would be out of the screen, with the width/height's end also out of the screen, I couldn't get the screen's menu option to fix this (which I did in the past on different screen/machine), after googling about it I had to use Nvidia's app to resolve the issue to shrink things down, could it be related perhaps?
Edit : Ok I tried to reproduce on video on a different mirc install and couldn't, went back to my main install which had the bug and wiped out mirc.ini to try to recreate and couldn't. I finally reproduced it, I was just missing some steps. Video in pm. It looks like the missing steps are actually using the favorites to join minimized, but also the server list to auto connect & minimized.