Recently I'm just deleted config folder and found that minecraft won't start because fastcraft don't know how to create config folder 
Code
[03:05:39] [main/ERROR] [LaunchWrapper/]: Unable to launchjava.lang.RuntimeException: Error saving user config at fastcraft.LoadingPlugin.<init>(F:69) ~[fastcraft-1.20.jar:?] at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:1.8.0_40] at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) ~[?:1.8.0_40] at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) ~[?:1.8.0_40] at java.lang.reflect.Constructor.newInstance(Unknown Source) ~[?:1.8.0_40] at java.lang.Class.newInstance(Unknown Source) ~[?:1.8.0_40] at cpw.mods.fml.relauncher.CoreModManager.loadCoreMod(CoreModManager.java:458) ~[forge-1.7.10-10.13.2.1307-1.7.10.jar:?] at cpw.mods.fml.relauncher.CoreModManager.discoverCoreMods(CoreModManager.java:346) ~[forge-1.7.10-10.13.2.1307-1.7.10.jar:?] at cpw.mods.fml.relauncher.CoreModManager.handleLaunch(CoreModManager.java:214) ~[forge-1.7.10-10.13.2.1307-1.7.10.jar:?] at cpw.mods.fml.relauncher.FMLLaunchHandler.setupHome(FMLLaunchHandler.java:90) ~[forge-1.7.10-10.13.2.1307-1.7.10.jar:?] at cpw.mods.fml.relauncher.FMLLaunchHandler.setupClient(FMLLaunchHandler.java:67) ~[forge-1.7.10-10.13.2.1307-1.7.10.jar:?] at cpw.mods.fml.relauncher.FMLLaunchHandler.configureForClientLaunch(FMLLaunchHandler.java:34) ~[forge-1.7.10-10.13.2.1307-1.7.10.jar:?] at cpw.mods.fml.common.launcher.FMLTweaker.injectIntoClassLoader(FMLTweaker.java:126) ~[forge-1.7.10-10.13.2.1307-1.7.10.jar:?] at net.minecraft.launchwrapper.Launch.launch(Launch.java:115) [launchwrapper-1.11.jar:?] at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.11.jar:?]Caused by: java.io.FileNotFoundException: D:\Games\Minecraft\Forge 1.7.10\config\fastcraft.ini (Системе не удается найти указанный путь) at java.io.FileOutputStream.open0(Native Method) ~[?:1.8.0_40] at java.io.FileOutputStream.open(Unknown Source) ~[?:1.8.0_40] at java.io.FileOutputStream.<init>(Unknown Source) ~[?:1.8.0_40] at java.io.FileOutputStream.<init>(Unknown Source) ~[?:1.8.0_40] at fastcraft.LoadingPlugin.<init>(F:1371) ~[fastcraft-1.20.jar:?] ... 14 more