Following several unsuccessful attempts to install the Windows Server 2012 R2 Update for x64-based Systems (KB2919355), each of which produced error code 80070002,

1. Verify that Windows Update KB2919442 is installed by examining Control Panel\System and Security\Windows Update\View update history and, if not, download and install it (http://www.microsoft.com/en-us/download/details.aspx?id=42162)
2. Download the Windows Windows Server 2012 R2 Update for x64-based Systems (KB2919355, published 4/16/2014) (http://www.microsoft.com/en-us/download/details.aspx?id=42335), including all six files:
Windows8.1-KB2919355-x64.msu
Windows8.1-KB2932046-x64.msu
Windows8.1-KB2934018-x64.msu
Windows8.1-KB2937592-x64.msu
Windows8.1-KB2938439-x64.msu
Windows8.1-KB2959977-x64.msu
3. If it does not already exist, add an empty System Tools folder to C:\ProgramData\Microsoft\Windows\Start Menu\Programs
4. Run the following command with administrative privileges:
dism /online /remove-package /packagename:Package_for_KB2919355~31bf3856ad364e35~amd64~~6.3.1.14
5. Reboot PC
6. Run the following two commands with administrative privileges:
     dism /Online /Cleanup-image /Restorehealth
     dism /online /cleanup-image /startcomponentcleanup
7. Run the Microsoft Fixit tool for Windows Update (http://support.microsoft.com/kb/971058)
8. Select and run “Cleanup system files” by using the Disk

9. Reboot Windows Server 2012 R2
10. Temporarily disable anti-virus software while executing the following step
11. Manually install the updates (downloaded in step 2) in the following order:
KB2919355
KB2932046
KB2959977
KB2937592
KB2938439
KB2934018

At the point of running KB2919355 i got a new error 0x800f0902

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TrustedInstaller

Check and see if start is set to manual or automatic this article explains it 3 = manual, 2=auto (it cannot be changed through registry)

http://support.microsoft.com/kb/968440

start the service mentioned in the article to and change to automatic and the manual update instals with a reboot notification.