Alright, this issue has become quite frustrating to me. The first time it happened, I started up the launcher as usual, but I noticed that the green load bar was about a quarter of the way, and it was moving very slowly. It usually takes only a couple of seconds, so I knew something was up. I went to the development console and the console was getting SPAMMED with warnings that some files could not be downloaded. This went on for about 8 minutes, and then finally it said that it gave up trying to download the files, and started the game for me. But, I noticed that some sounds were missing, such as chest opening (closing worked), tossing xp bottles, and more. So I cleaned up my .minecraft and re-downloaded the .exe itself, but to no avail, the same thing happened. So here I am, hoping to get an explanation of some sorts.

What I expected to happen was...:
All the files get downloaded by the launcher like usual, in a short amount of time.

What actually happened was...:
The launcher kept trying to download some files, but after 8 minutes of failure, it gave up trying to download the files and just started the game for me, and in-game I noticed that some sounds were missing.

Steps to Reproduce:
1. Start the launcher.
2. Go to the development console.
3. Look at all the warnings for file download failure.
4. Wait some time until it gives up trying to download the files.
5. Go into a SP world or multiplayer (doesn't matter), and try to open a chest, or throw an XP bottle, notice how there is no sound for them.

If you have any questions about my computer, etc, I'll do my best to answer!

P.S. I have tried to re-download everything multiple times now, and I also know that this will be a dupe of another issue I saw, but it was closed and I did not understand the answer.