1. Open Avast, this may be in your hidden icons on the bottom bar of your Windows screen

2. Once you've opened Avast, click on the Protection tab which will open this window

3. Click on "Core Shields". It will take you to this screen

4. Click on "Settings". I've highlighted on this screenshot with a red arrow

5. Then you'll see this. Turn Core Shields "Off" - select the 10 minute option

Ignore the rest of it
Then run the launcher, and turn Core Shields immediately back on again once you've got RoR running. You can then close Avast and it will continue to run as normal without affecting RoR