This is where your (KB4056892) is stored on your hard drive folder: - %windir%\softwaredistribution\download
Depending upon the updates, different folders get created on the above location.
For clearing the contents of the softwaredistribution folder, try the below commands on the command prompt.
Type cmd in search and Run as administrator then type as follows;
net stop wuauserv
rmdir %windir%\softwaredistribution /s /q
net start wuauserv
exit