If the "launcher.pack.lzma" file is missing from the .minecraft directory, starting the launcher will show the following output:

Bootstrap started
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma

The launcher will stay like this for at least a few minutes (approximately), until continuing normally. In some tests, the launcher would stay like this indefinitely.

Before this problem, the launcher was expected to start normally, and end at the login/play screen.

Steps to Reproduce:
1. Remove the launcher.pack.lzma from the .minecraft directory
2. Start the minecraft launcher