Windows 2008 R2 IIS 7.5
MS-SQL 2012
MediaWiki 1.32.0-RC0 (11-09-2018)
I had tried 1.31.1 but from reading found it doesn't support MS-SQL at all because of issues with it and it was being fixed in 1.32.0 release. Looking in GIT I saw most of those issues resolved. When I first try to install there's an error on table creation, it looks like a comma was left out of the tables.sql file.
maintenance\mssql\tables.sql line 1044
rc_patrolled tinyint NOT NULL CONSTRAINT DF_rc_patrolled DEFAULT 0
I added the comma to the end in that file and started the entire process over after deleting and remaking a blank DB. After fixing that though it installs the DB and moves on but errors after that.
Install
Setting up database... done
Creating tables... done
Creating database user... done
Populating default interwiki table... done
Initializing statistics... done
Generating secret keys... done
Prevent running unneeded updates... done
Creating administrator user account... done
Creating main page with default content... failed
Information
Could not create a new page. It already exists.