Me too, it seems a lot of people having this issue.I can't install Security Update for Internet Explorer Flash Player for Windows 10 for x64-based Systems (KB3087040) through Windows Update. Every time i try to retry the download it always fail with a error code 0x80004005.
Have you try it? Is it safe?Did you try to install it manually ??Try to download the file from post 27http://www.tenforums.com/windows-updates-activation/23496-windows-update-error-0x80004005-kb3087040-3.html (worked for me)
ps:My apologizes if it is against the rules to put solutions from other forums