It seems like mirc does not start if its executable is named different from mirc.exe. This kind of protection is okay with me, but it should at least allow itself to be renamed to mirc2.exe mirc3.exe so you can distinguish between several running mirc-instances in the task-manager.

I can only assume you didn't actually try to rename it mirc2.exe, because if you had you would've seen that mIRC does allow the file to be renamed provided it starts with 'mirc'.

I had no problems renaming it to mirc32 { to Make Spr Jukebox update my music list} what you have to do is close mirc so it isnt running and it will rename just fine