Missing DirectX updates prevent some Rift apps from starting

[doedoejohn]

Solved an issue that prevented us from running some Rift apps. Here are our troubleshooting steps in case someone has the same issue.

Platform is a fresh Win7 install on an HP Z640 workstation, Intel Xeon CPU E5-2660 v3 @ 2.60GHz, NVIDIA GeForce GTX 980, all updates applied (or so we thought!).

Installed Oculus for our brand new Rift. We can start 'Oculus Video' and 'Lucky's Tale' without a problem. Then installed 'Oculus Dreamdeck' and 'Farlands' apps, but couldn't start either.  From Oculus Home -> Library -> Installed, clicking on 'Start' on either app would not do anything, no error shown on screen.

Looked at the latest logs (C:\Users\{username}\AppData\Local\Oculus\Service_*.txt) where we found this error after trying to launch Dreamdeck:

{WARNING} [ApplicationPackage] App oculus-dreamdeck has exited with error: 3221225781
{!ERROR!} [LibraryItem] Error returned from library item oculus-dreamdeck
{!ERROR!} [OAF ERROR] LifeCycle\LifeCycleAppTracker.cpp(123) : App exited unexpectedly: oculus-dreamdeck (1971039)
{INFO}    [LifeCycle] Removing Tracker: 2420 (oculus-dreamdeck)
{INFO}    [LifeCycle] App exited unexpectedly: App exited unexpectedly: oculus-dreamdeck (1971039)

Searching the web for the error exit code (3221225781 or 0xC0000135) yielded nothing relevant to Oculus. So we launched the app from a command line window:

E:\Oculus\Software\oculus-dreamdeck\WindowsNoEditor\Dreamdeck\Binaries\Win64>Dreamdeck-Win64-Shipping.exe

An error window popped up: "The program can't start because X3DAudio1_7.dll is missing from your computer. Try reinstalling the program to fix this problem."  

This problem with Oculus (missing X3DAudio1_7.dll) already has a solution here. In a nutshell, need to install DirectX updates that are not part of a fresh DirectX install, as explained here.  We downloaded the "DirectX End-User Runtimes (June 2010)" from here.

Hopefully this info helps!