P70 Win10: Lenovo-provided Realtek HD Audio driver installer does not install Dolby Audio

Very strange.  My P70 was purchased in 2016 with Win7 Pro pre-installed (because that's what I wanted).  In 2018 I installed Win10 in a second partition, in order to try it out and learn about it.  Earlier this year I made Win10 my default operating Windows, but kept the Win7 partition.  This past week I finally deleted the Win7 partition and re-installed Win10 (1909) from scratch in this now available space, just to "clean house" now that I've had almost two years of experience and learning about Win10.  My original Win10 partition was installed with 1511, and over the years came through major upgrades 1709, 1803, 1809, 1903 and just recently 1909. That's why I decided to celebrate the demise of Win7 with a clean start using a new Win10 1909 installer.

Anyway, everything is fine with the resulting Win10.  Except that today I noticed I was missing the Dolby Audio X2 app I was quite sure I had, for sure in my now deleted Lenovo factory pre-installed Win7, and perhaps in the Win10 I installed in 2018 (but I can't be absolutely sure).  But for sure it was not there earlier today when I started looking into this.  Strangely, in Sound there is a Dolby tab which indicates that Dolby Audio is ON (and can be toggled OFF), so the Realtek driver supporting Dolby Audio sound appears installed properly. But the separate Dolby Audio app (which provides five EQ preset choices as well as a manual cusomizable 20-band graphic EQ) is not installed.

Note that the "retail" Win10 installer I used comes MS, not from Lenovo Recovery Media. And of course the Win10 install found drivers for 100% of the P70 hardware, without having to run Lenovo System Update of Lenovo Vantage to get everything updated.  Nevertheless after completing the initial Win10 install I DID install Lenovo Vantage and ran System Update.  There might have been one driver update (for Synaptic touchpad I think, but can't recall exactly) and I ran that.

What's important here is that I was missing the Dolby Audio app, and it obviously didn't get installed by Lenovo Vantage or Win10 install.  I had operating up-to-date Realtek Drivers but no Dolby Audio app.

I remember something like this in the past, either when I upgraded my W530 laptop from HDD to SSD and reinstalled Win7, or perhaps back in 2018 when I first installed my "practice" Win10 partition.  Can't remember exactly what was the situation but I have a deja vu of going through this in the past.  I believe the solution involved manually running the Lenovo-provided installer for the Realtek HD Audio device, which also installed the Dolby app... at least for Win7.  This isn't happening for Win10 today, running the latest available Lenovo-provided Realtek driver installer.

Looking closer, it turns out there is a DAX2 sub-folder in C:DriversWinAudio, which contains an installer file named dax2_app_release_x64.msi, which IS the installer file for the Dolby Audio app.  And of course this sub-folder is created when you run the Lenovo-provided Realtek driver installer.  But it appears this installer IS NOT RUN BY THE INSTALL SCRIPT!!!  So you don't end up with the Dolby Audio app getting installed!!!

I discovered this today (because of my partial memory about how I solved this in the past, from my deja vu) and manually ran that DAX2 installer.  And sure enough the Dolby Audio app is now installed, it shows up in Control Panel, it runs and works, etc. Great!  So why didn't it get installed when I ran the latest Lenovo-provided Realtek installer n1ca508w.exe?  Don't know.

I then decided to just re-run n1ca508w.exe (with the Dolby Audio app already just installed).  It did what it does (which probably starts off with a full uninstall of currently installed drivers and software), and at the end I looked to see what got installed.  Sure enough, just like before, the current Realtek driver was installed, but the Dolby Audio app I had just five minutes earlier manually installed was now DISAPPEARED!!  It obviously got uninstalled at the start of the new driver installer script, and once again NEVER GOT INSTALLED AS PART OF THE SCRIPT!

So, once again, I manually ran that MSI installer in the DAX2 sub-folder. And sure enough once again the Dolby Audio app is now back and fully operational.

Clearly seems to be a bug in the Lenovo installer script, if you ask me.

Anyway, in the end what's most important to me is that Lenovo IS providing the Dolby Audio app in their driver installer package, even if it's not getting run.  But you can manually run the MSI file in the resulting DAX2 sub-folder to complete its install.  I happen to prefer the user interface of the older Dolby Theater app that was provided with the older W530, but I can certainly live with Dolby Audio from DAX2.

I'm providing this just in case anybody else can benefit from this discovery.