When upgrading to 9.3SP1 or installing a new 9.3SP1 site the Solr configuration menu item can disappear making it look like Microsoft Search Server is used. The status button will also return an error stating "No status information could be retrieved."
You may also see failed connections like this.
Run the SetSearchProvider utility on the CMS server and set the site to Solr.
"DriveLetter:\Program Files (x86)\Ektron\CMS400v93\Utilities\SetSearchProvider\SetSearchProvider.exe"