Siemens Industry Online Support
Siemens AG
Entry type: FAQ Entry ID: 109741420, Entry date: 10/04/2016

In TIA Portal V14 why can you not establish a connection to the Multiuser server?

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For system-specific reasons it is sometimes not possible to establish a connection to the Multiuser server even when you fulfill the criteria for the authorization.

The two cases below give the causes and remedies when you cannot establish a connection to the Multiuser server (via the "Manage Multiuser Projects…" dialog, for example).

Case 1
You have been added as user to one of the authorization groups for the project, but it is nevertheless not possible to establish a connection.

With Multiuser there are different authorization groups for the projects and for the server. In this case you are entered as user in the project-wide group.

To be able to establish a connection to the server you have to be entered as user in the authorization group for the server.

Case 2
A connection is not possible even though you are authorized as user in the administrator group.

During querying of the authorization as administrator for access to the server the User Account Control (UAC) is expected in MS Windows 7 in order to upgrade you as user to administrator. The User Account Control is not displayed because this action is not performed by the TIA Portal and not by the user.


  • Add the user to another local group and then enter it in the Multiuser server authorization group.
  • Alternatively you can also disable the UAC in MS Windows 7. The UAC is enabled by default in MS Windows 7.

The User Account Control can prevent potentially dangerous programs from making changes on your computer. If you disable the User Account Control, your computer is vulnerable to potential security risks.

Fig. 1

Proceed as follows to open the settings for the User Account Control:

  1. In the MS Windows Start menu you select "All Programs > Accessories > Run" and in the text field you enter "msconfig".
  2. Click OK and confirm the message that appears with "Yes".
  3. In the "System Configuration" dialog that opens you select the "Tools" tab.
  4. Mark "Change UAC settings" and click "Start".
  5. Pull the controller completely down and confirm with OK to disable the User Account Control.

The behavior described above in Cases 1 and 2 will be cleared with TIA Portal V14+SP1.

Further Information
More information about the authorization groups is available in the manual "SIMATIC STEP 7 Professional V14.0" under Managing User Groups.

Security information
In order to protect technical infrastructures, systems, machines and networks against cyber threats, it is necessary to implement – and continuously maintain – a holistic, state-of-the-art IT security concept. Siemens’ products and solutions constitute one element of such a concept. For more information about cyber security, please visit