In my case repetitive attempts to install KB2919355 through Windows Update would successfully download the package, but fail during actual installation with error code 0x80070002. A quick examination of log file at
showed that the updated seemed to be reporting a failure after attempting to access the following directory
C:\ProgramData\Microsoft\Windows\Start Menu\Programs\System Tools
In my case that directory simply did not exist, since a while back I moved it to ...\Start Menu\Programs\Accessories\System Tools location. I didn't expect this change to break anything. In an attempt to fix the problem I created an empty ...\Start Menu\Programs\System Tools directory and restarted the updater. To my surprise, the update installed flawlessly.
A similar account is available here, where installation failure was triggered by a different missing directory.
Apparently Windows 8.1 update mechanism is very sensitive to the "default" directory structure, even when it comes to directory structures that we often regard as fairly cosmetic (like "start menu" structure, as it happened in my case). I believe that in this specific case the update installer should have been able to correct this minor problem automatically instead of confusing users with numerical error messages.
Anyway, if you are getting 0x80070002 from the updater, try looking into CBS.log. The reason for the failure might be immediately visible and it might be something as simple as a missing directory path in the "start menu" structure.