Add A SharePoint Server Farm Admin Farm-Wide

I was installing a new SharePoint Server 2019 farm and after applying all updates and configuring the SharePoint Products Wizard, I restarted my servers a final time and logged on, only to find that I couldn’t access the SharePoint Products Wizard anymore.

I was receiving an “Access Denied” error when trying to connect to the SharePoint Configuration Database.  After scratching my head for a while, I realized I had added a  local account to the Farm Administrator instead of my  domain account.

Fortunately, there was a reasonably easy fix.  We’ve got it documented at https://docs.microsoft.com/en-us/powershell/module/sharepoint-server/add-spshelladmin?view=sharepoint-ps, but of course, there’s stuff that we leave out.  This is how I solved that problem.

1. Launch SharePoint Management Shell using RunAs Other User and enter the credentials of a current farm administrator (in this case, my local account).
2. Copy/paste this bad boy:

   Function New-FarmAdmin ([string]$Identity,[switch]$IncludeAllContentDatabases)
   {
      $CentralAdminWebApp = Get-SPWebApplication –IncludeCentralAdministration | ? {$_.DisplayName –like "SharePoint Central Administration*"}
      New-SPUser –UserAlias $Identity –Web $CentralAdminWebApp.URL –Group "Farm Administrators"
      $CentralAdminContentDB = Get-SPContentDatabase –WebApplication $CentralAdminWebApp
      Add-SPShellAdmin -Database $CentralAdminContentDB -Username $Identity
      If ($IncludeAllContentDatabases)
      { 
         $ContentDatabases = Get-SPContentDatabase
         Foreach ($Database in $ContentDatabases) 
            {
            Add-SPShellAdmin -Database $Database -Username $Identity
            }
      }
   }

3. Run New-FarmAdmin -Identity <DOMAIN\Username> -IncludeAllContentDatabases
4. Celebrate.  Beer optional.

Happy Farming!