There's a problem with the client right now, you just need to go into Task Manager and stop any RuneMate process you can see then run the RuneMate app as normal. If you're using the standalone version, just redownload it.
this is the problem. every time I open the app its updating, after the bar of update % completes the app closes and it shut's down. And every time I try to open it comes again whit update.. There is like when it's updating I can open the app again, and then I can see the log in screen, but whet I try to log in, its says the same..try to update..
download the installer from the website again and run the installer, there will be an option while running the installer to update current runemate, should fix it.
problem is that right now runelite is not supported... who knows for how long