<div>
I do not know the reason, But when I repair using 2014 installation - it has successfully upgraded
</div>


I do not know the reason, But when I repair using 2014 installation - it has successfully upgraded

<div>
Repair would have rebuilt the databases, which is why all open connections would have been killed and hence you are now able to connect.
</div>


Repair would have rebuilt the databases, which is why all open connections would have been killed and hence you are now able to connect.

<div>
I have 12 more servers to upgrade - How can I make sure all connections are killed before the upgrade so that the error may not repeat - any idea
</div>


I have 12 more servers to upgrade - How can I make sure all connections are killed before the upgrade so that the error may not repeat - any idea

<div>
<div class="content wysiwyg-content">
I am trying to upgrade SQL 2012 to SQL 2014 Express (SCCM Secondary Site). &nbsp;Database engine has failed and Reason: Server is in single user mode. Only one administrator can connect at this time...<br />
How to solve this issue?
</div>
</div>


I am trying to upgrade SQL 2012 to SQL 2014 Express (SCCM Secondary Site).  Database engine has failed and Reason: Server is in single user mode. Only one administrator can connect at this time...
How to solve this issue?

Upgrade SQL 2012 to SQL 2014

Microsoft SQL Server is a suite of relational database management system (RDBMS) products providing multi-user database access functionality.SQL Server is available in multiple versions, typically identified by release year, and versions are subdivided into editions to distinguish between product functionality. Component services include integration (SSIS), reporting (SSRS), analysis (SSAS), data quality, master data, T-SQL and performance tuning.

Microsoft SQL Server

Systems Center Configuration Manager (SCCM, formerly known as Systems Management Server) is Microsoft’s system software for managing large groups of not only Microsoft computers, but those running other operating systems, such as Linux, OS-X, and various mobile technologies.