Normally you should be able to run our client by a simple double click after installing Java (version 8 or higher), however sometimes issues may occur. In that case you can follow these steps:
Open up a terminal (On Windows: Start > Run > type 'cmd.exe') and in run 'java -version'. This should return with a message similar to 'Java version 1.8' or a higher number. Otherwise check your Java installation (and verify it's added to your environment path).
Open up your user directory (On Windows: 'C:\Users\You'), you should find a folder named 'RuneRealmCache' try deleting this folder and restarting the client.
Contact staff in-game or discord
for the fastest response.
You can also reach us at firstname.lastname@example.org