error when launching most of the time- "could not find or load net.minecraft.client.main.Main"

Most of the time when I launch the game in the snapshots, the blue download bar at the bottom will increment slower than normal, get almost to the end, go back a little ways and then it simply quits out, displaying the following error message:

Error: Could not find or load main class net.minecraft.client.main.Main
Java HotSpot(TM) 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release

Most of the time this comes up, but occasionally it will work and launch as normal. If this is a bug, please fix it! If this on my end, could you please tell me how to resolve the error?

-Launch minecraft as normal
-See if what I described occurs. I have not seen any other bugs reported on this, so I believe it is on my end.