update failed?! in Voltz Discussion Posted March 24, 2013 I know a solution that works for every modpack and version. 1. Clear cache 2. Go to C:\Users\User\AppData\Roaming\.techniclauncher\cache 3. Download the right VANILLA minecraft.jar(tekkit needs 1.2.5, the latest voltz needs 1.4.7) 4. Rename that jar to "minecraft_1.2.5.jar" or "minecraft_1.4.7.jar" 5. Put it in that cache file shown in step 2 6. Run the launcher and play NOTE: Dont click clear cache again or it may be ruined again. This worked for me, except for step #4, I had to rename the file specifically to "minecraft_1.4.7" or it didn't work. Thanks for the tip.