cant launch minecraft

so was just bout to play minecraft and got a launcher update when i open it, after i tried to launch mc it crashed and i got this crash message Error: Could not find or load main class net.minecraft.client.main.Main
Java HotSpot(TM) Client VM warning: Using incremental CMS is deprecated and will likely be removed in a future release
anyone got a fix? ive tried uninstalling mc and it didnt work :/