When i try to launch minecraft it comes up with a list of messages and one is highlited red with the word error next to it

Name: nds_de.lang
URL: http://resources.download.minecraft.net/85/8588397bcb47d981cc4746d182fb71ba5431cf96
Error details: Attempting to move successful download to C:/Users\leslie\AppData\Roaming\.minecraft\assets\objects\85/8588397bcb47d981cc4746d182fb71ba5431cf96 The process cannot access the file because it is being used by another process
Filename on disk: 1ca8-b0ca-131f-bfdd
Path: C:\Users\leslie\AppData\Local\Temp\1ca8-b0ca-131f-bfdd
Exists: file