when I pressed play an error popped up

It says

Unable to save download. af_za.lang
Name: af_za.lang
URL: http://resources.download.minecraft.net/9b/9bfd7f84af1b17f0285868ff5f8dac3746394653
Error details: Attempting to move successful download to C:/Users\biztosz\AppData\Roaming\.minecraft\assets\objects\9b/9bfd7f84af1b17f0285868ff5f8dac3746394653
The process cannot access the file because it is being used by another process
Filename on disk: 1ab2-73c7-e6c5-7fa6
Path: C:\Users\biztosz\AppData\Local\Temp\1ab2-73c7-e6c5-7fa6
Exists: file