I have never had any previous issues updating Lightroom until attempting to update to 2015.12.
I cannot update through Creative Cloud - I tried manually checking for updates.
I tried refreshing the CC desktop app.
I tried signing out and in.I tried removing the OPM.db file.
I removed Lightroom CC 2015.10 and reinstalled it, but then only version 2015 got installed - the very basic and first version.
I cannot install Lightroom CC 2015.12 manually through the installer from the downloads section on the adobe site and that gives me this error EVEN IF I choose "Run as administrator".
I am stumped as to what to do or try next.
I have even tried using Lightroom Help->Updates, but that is grayed out and cannot click on it, even when I was on Lightroom CC 2015.10.
Close all the Applications.
Open the location mentioned below
C:\Program Files(x86)\Common Files\Adobe\AAMUpdaterInventory\1.0
There will be a AdobeUpdaterAdminPrefs.dat. Either delete it or open it in notepad and then change the value from 1 to 0. Save it.
Then run the Installer update once again.
Thank you very much!
After some trial and error I finally got to update Lightroom thanks to your tip!
You are most welcome. I am glad it worked for you!