The launcher doesn't load any version I try to play it just loadsthen says errorcan't download that versions.jar.

Put the summary of the bug you're having here

What I expected to happen was...:
Describe what you thought should happen here

What actually happened was...:
Describe what happened here

Steps to Reproduce:
1. Open the launcher.
2. Select snapshot 17w06a.
3. Hit play.
4. Doesn't load and says, ERROR Unable to save download. 17w06a.jar