Have you experienced this issue before with previous versions of mIRC?
Are you running any other applications in the background, such as anti-virus or security software?
If you restart your computer and try again, do you see the same issue?
I've only noticed it on the past 2 (7.36 and 7.34).
My antivirus is avira. Task Manager reports the following things are running: avgnt.exe, avgyard.exe, avira.OE.ServiceHost.exe, Avira.OE.Systray.exe, avshadow.exe, sched.exe. Not sure if this would cause any problems or not.
If I restart my computer, I can reproduce it.
Let me know if I should run anything else to test it.