Database times out during upgrade with the following error in the upgrade log file:
Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding.
You can re-run the installer again to determine if the timeout was due to a sporadic networking issue.
If the timeout continues you can temporarily change the SQL Remote Connection timeout value on your SQL. You can find this setting in SQL Server Management Studio by right clicking on he server name in the Object Explorer window, and selecting properties.
Then, from the menu on the left side of the window select "Connection". Under "Remote server connection" make sure the "Allow remote connections to this server" box is checked. You can change the default value for "Remote query timeout" to "0" for the duration of the DB upgrade.
If the installer times out again you can run the installer locally on the Database server rather than remotely from the Console or Device Services server.
NOTE: The installer requires .NET 4.5.2 to run properly. If you do not have .NET 4.5.2 the installer will prompt you to installer it, and will possibly prompt you for a server reboot once it is installed. If you do not want to reboot the server please continue running the installer remotely.