There is no default instance of SQL Server on the computer

Sometime when trying to browse the SSIS packages from SQL Server Management Studio the following error can come:

The SQL Server specified in Integration Services service configuration is not present or is not available. This might occur when there is no default instance of SQL Server on the computer. For more information, see the topic "Configuring the Integration Services Service" in SQL Server 2008 Books Online.

This error is coming when the default instance runs on a different port than the default one (1433) or when you have only named SQL instances on the machine. 

To solve the error you had to make some changes in the MsDtsSrvr.ini.xml file:

SQL 2005 location:
C:\Program Files\Microsoft SQL Server\90\DTS\Binn\MsDtsSrvr.ini.xml

SQL 2008 location:
C:\Program Files\Microsoft SQL Server\100\DTS\Binn\MsDtsSrvr.ini.xml

SQL 2012 location:
C:\Program Files\Microsoft SQL Server\110\DTS\Binn\MsDtsSrvr.ini.xml

Modify the MsDtsSrvr.ini.xml file to point to the your named instance or to the default instance with the right port, and then restart the SSIS service:

<?xml version="1.0" encoding="utf-8"?>

<DtsServiceConfiguration xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

  <StopExecutingPackagesOnShutdown>true</StopExecutingPackagesOnShutdown>

  <TopLevelFolders>

    <Folder xsi:type="SqlServerFolder">

      <Name>MSDB</Name>

      <ServerName>SERVER_NAME\INSTANCE_NAME</ServerName>

    </Folder>

    <Folder xsi:type="FileSystemFolder">

      <Name>File System</Name>

      <StorePath>..\Packages</StorePath>

    </Folder>

  </TopLevelFolders>

</DtsServiceConfiguration>

OR:

<?xml version="1.0" encoding="utf-8"?>

<DtsServiceConfiguration xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

  <StopExecutingPackagesOnShutdown>true</StopExecutingPackagesOnShutdown>

  <TopLevelFolders>

    <Folder xsi:type="SqlServerFolder">

      <Name>MSDB</Name>

      <ServerName>SERVER_NAME,PORT_NUMBER</ServerName>

    </Folder>

    <Folder xsi:type="FileSystemFolder">

      <Name>File System</Name>

      <StorePath>..\Packages</StorePath>

    </Folder>

  </TopLevelFolders>

</DtsServiceConfiguration>