Whenever the launcher plays it says the item in the description

Name: thunder2.ogg
URL: http://resources.download.minecraft.net/a2/a20cbf2ddce541eaed520d7ec55665fe97428be6
Error details: Cannot create a file when that file already exists
Filename on disk: 6e62-1099-aa3f-3258
Path: C:\Users\STUFF\AppData\Local\Temp\6e62-1099-aa3f-3258
Exists: file