In the ALM deployment logs the following error will exist...
com.hp.alm.platform.exception.CTdException: Failed to fetch repository path from old SA schema <site_admin_schema_name>
This is caused by a bug in the ALM 15.5.1 deployment mechanism
Download the hotfix
Unxip the hotfix to expose the file: alm-install.jar
During ALM deployment, on the last panel when the installation is completed but before clicking the "Next" button to deploy, copy "alm-install.jar" and replace the existing "alm-install.jar" in the following typical paths...
<drive>\Program Files\Micro Focus\ALM\lib
Mind that paths can be different. The above are common
Once the "alm-install.jar" is in place click "Next" in the installation GUI to start the deployment process.
The ALM Site Administration database on MSSQL using WinAuth should now upgrade.
This fix will be committed to the following ALM builds...
ALM 15.5.1 Patch 02
ALM 16 (general release)