I had this problem a year ago, then I updated my graphic cards' drivers and it fixed it. Recently I updated windows, and the problem arrived. All my drivers are up to date and the problem persists. Yeah, I tried messing with the compatibility modes, nothing helps. Tried matt's client as well, no luck.
Hey man, it did not fix my problem. I honestly don't understand how this server works. I just updated my Windows 10 and the problem returned.
Re-installing windows. Updating ALL drivers. Removing and re-installing MapleRoyals like 500 times. Ran as Admin. Messed with every compatibility mode. Changed Hz rate of the screen. Tried the lolwut software and Matt's client. Restarted PC like 500 times. Disabled Anti-virus / Windows firewall. Disabled the drivers and re-enabled them back. Look, MapleRoyals has worked JUST FINE, until the windows update I had a couple days ago. The problem occurred as soon as I updated Windows.
Create a custom resolution of 800x600x60hz. Launch game once in that resolution, it may or may not launch. You need to try it at least once. After that change back to your original resolution and try launching the game, should open up.