I did this on Windows 10 - version 1709.
What worked for me was going to the Microsoft Update Catalog and doing a search for "Realtek Sound Driver", here's the link: https
/www.catalog.update.microsoft.com/Search.aspx?q=...
Then I sorted the results by clicking on the "Last Updated" column, which put the most recent drivers at the top. The second item listed [this will change over time] was version 6.0.1.8346, size 134.3 MB. I downloaded the .cab file and used 7zip to extract it to a folder.
Then I installed it manually using Device Manager, i.e.: Under "Sound, video & game controllers", I right-clicked on "Realtek High Definition Audio" and clicked on "Update drivers", then -> "Browse my computer..." and navigated to the folder with the unpacked driver files. Be sure you have check-marked "Include subfolders".
The driver installed with no problems. I am now running the latest driver, AND the Realtek Audio Manager has returned.