I get this message every time I try to launch Minecraft 1.8.7. I was using the mods Optifine and Mineshafter, but I disabled them, and the same thing still happens. Given that this is a problem with vanilla Minecraft, how can I fix this?
Check if your Java is up to date. You can verify your java here -> https://www.java.com/en/download/installed.jsp
Your problem is right here:
Knowing this, your best option would be to create a new profile and start from scratch. When you modded the other profile, something somewhere got corrupted.
To delete an old profile and make a new one:
- Navigate to the Profile Editor tab.
- Right-click the profile that is giving you issues.
- Hit Delete Profile and confirm the action.
- Right-click on the blank space and select Add Profile.
- Usually you don't need to choose any settings, but make sure that "Use Version" is set to "Use Latest Version"
- Launch this new profile.
Now, this will break mods because you're not running on a modded profile. To reinstall your mods, carefully follow the instructions from your original mod poster. Personally, I would recommend that you install Minecraft 1.8 (Use Version should be set to Minecraft 1.8) and then install Forge. Install all the required mods.