2023-09-07 20:20:43 [SEVERE] [ForgeModLoader] The minecraft jar file:/D:/MultiMC/libraries/com/mojang/minecraft/1.6.4/minecraft-1.6.4-client.jar!/net/minecraft/client/ClientBrandRetriever.class appears to be corrupt! There has been CRITICAL TAMPERING WITH MINECRAFT, it is highly unlikely minecraft will work! STOP NOW, get a clean copy and try again!
2023-09-07 20:20:43 [SEVERE] [ForgeModLoader] For your safety, FML will not launch minecraft. You will need to fetch a clean version of the minecraft jar file
2023-09-07 20:20:43 [SEVERE] [ForgeModLoader] Technical information: The class net.minecraft.client.ClientBrandRetriever should have been associated with the minecraft jar file, and should have returned us a valid, intact minecraft jar location. This did not work. Either you have modified the minecraft jar file (if so run the forge installer again), or you are using a base editing jar that is changing this class (and likely others too). If you REALLY want to run minecraft in this configuration, add the flag -Dfml.ignoreInvalidMinecraftCertificates=true to the 'JVM settings' in your launcher profile.
2023-09-07 20:20:43 [SEVERE] [ForgeModLoader] For your safety, FML will not launch minecraft. You will need to fetch a clean version of the minecraft jar file
2023-09-07 20:20:43 [SEVERE] [ForgeModLoader] Technical information: The class net.minecraft.client.ClientBrandRetriever should have been associated with the minecraft jar file, and should have returned us a valid, intact minecraft jar location. This did not work. Either you have modified the minecraft jar file (if so run the forge installer again), or you are using a base editing jar that is changing this class (and likely others too). If you REALLY want to run minecraft in this configuration, add the flag -Dfml.ignoreInvalidMinecraftCertificates=true to the 'JVM settings' in your launcher profile.