Here is a Batch script to empty the SoftwareDistribution Folder. It stops any installer processes in the background, temporarily disables the Windows Update Service, deletes everything in the Software Distribution folder then sets the Windows update service back to automatic and starts the service.
@echo off
CD C:\
taskkill /F /im setup.exe
taskkill /F /im ose00000.exe
taskkill /F /im msiexec.exe
sc config wuauserv start= disabled
net stop wuauserv
PowerShell.exe Remove-Item C:\Windows\SoftwareDistribution\* -Force -Recurse
sc config wuauserv start= demand
net start wuauserv
Brandan got a reaction from Paul in Script to empty SoftwareDistribution Folder. Clear out Windows updates.