Resolving Erroneous OS Server Basic License Warnings on PCS 7 Single-Station Projects

In SIMATIC PCS 7, when an Operator Station configured as an OS Single Station and possessing a valid OS Single Station license periodically triggers licensing warnings demanding an 'OS Server Basic' (or WinCC Server) license, the cause is a project type misconfiguration in WinCC Explorer. If the project was originally generated from a server template or contains a Reference OS, WinCC flags the project type as a 'Multi-User Project' rather than a 'Single-User Project'. In Multi-User mode, the WinCC runtime licensing engine strictly requires an OS Server license regardless of actual deployment. To resolve the warning without purchasing unneeded licenses, open Project Properties in WinCC Explorer, switch the Project Type from Multi-User to Single-User, restart WinCC Explorer, and re-activate runtime.

Executive Summary

Cost-effective, compact PCS 7 installations often deploy OS Single Stations, which combine engineering, server data archiving, and operator visualization onto a single physical PC. Siemens provides dedicated, cost-optimized 'PCS 7 OS Software Single Station' runtime licenses for this topology. However, commissioning engineers frequently encounter perplexing license failure banners during runtime: WinCC insists that a full 'OS Server Basic' license is missing. This occurs because internal project properties classify the station as a multi-user server. Realigning the project type in WinCC Explorer clears the erroneous server license demand and restores full licensing compliance.

Architecture and Fundamental Mechanics

The licensing verification architecture of WinCC within SIMATIC PCS 7 operates through explicit project type classifications:

WinCC Project Type Classifications:
* Single-User Project: Designed for autonomous single stations where WinCC Runtime executes locally on the machine hosting the project database. No remote OS Clients connect to this station.
* Multi-User Project: Designed for dedicated OS Servers that serve process graphics, alarms, and archive tags to multiple distributed OS Clients across the Terminal Bus.
* Client Project: Designed for thin OS Clients that load server data packages from remote servers.
The Licensing Demand Mechanism (CCLicExe.exe):
* When WinCC Runtime activates, the licensing subsystem inspects the project configuration database (.mdf).
* If the internal flag designates Multi-User Project, WinCC immediately queries Automation License Manager (ALM) for the SIMATIC PCS 7 OS Software Server (or WinCC Server) license key.
* If the station only has a SIMATIC PCS 7 OS Software Single Station license installed, ALM fails the query. WinCC triggers periodic license violation popups and logs missing server license events.
The Multi-User / Single-User Toggle Workaround:
* In some cases, project templates or projects featuring a 'Reference OS' become internally latched in Multi-User mode.
* Explicitly toggling the project type to Single-User resets the internal database flags, instructing the licensing engine to validate against the installed Single Station license.

Step-by-Step Implementation Procedure

Follow these procedures to correct the project type and eliminate erroneous OS Server license warnings:

Deactivate WinCC Runtime and Open Project Properties:
* On the target OS Single Station, deactivate WinCC Runtime.
* In WinCC Explorer, right-click the root project item in the navigation tree and select Properties.
Inspect Current Project Type:
* In the Project Properties dialog under the General tab, inspect the Type field.
* If it indicates Multi-User Project, the station is incorrectly requesting server licenses.
Switch Project Type to Single-User:
* Change the project type drop-down selection from Multi-User Project to Single-User Project.
* If WinCC displays a confirmation warning stating that multi-user client settings may be removed, confirm and click OK.
Execute Clean Project Reload:
* Close WinCC Explorer.
* Wait 10 seconds for all background database processes to detach.
* Reopen the project in WinCC Explorer.
Apply Toggle Workaround if Setting Reverts:
* If the project type stubbornly retains the server demand:
- Switch project type to Multi-User Project, click OK, and close WinCC Explorer.
- Reopen WinCC Explorer, switch project type back to Single-User Project, click OK, and close WinCC Explorer.
- Reopen WinCC Explorer. This double-toggle cleanses orphaned database registry keys.
Verify Reference OS Configuration in SIMATIC Manager (If Applicable):
* If your multiproject utilizes a second station as a Reference OS (e.g., an identical local backup station):
* In SIMATIC Manager Component View, ensure the primary OS station object is configured as a WinCC Application (Single Station) and that the secondary station is configured as WinCC Application (stby) or a matching Single Station reference.
Activate WinCC Runtime and Verify Licensing:
* In WinCC Explorer, click Activate.
* Verify that runtime starts smoothly without displaying server license warnings.

Verification

In Automation License Manager, open the License Keys view on drive C:. Confirm that SIMATIC PCS 7 OS Software Single Station indicates status 'OK' with zero missing license notifications. In WinCC Runtime, observe operational screens for 60 minutes; confirm that no demo mode banners or 'OS Server Basic license missing' popups appear.

Limitations and Operational Precautions

Converting an OS project to Single-User mode permanently disables the ability for remote OS Clients to connect to that station; if remote operator clients must access the station, a legitimate OS Server license package must be procured. Always maintain a project backup before modifying project properties.

Engineer FAQ

Why did my Single Station project demand an OS Server license?

The project properties in WinCC Explorer were set to 'Multi-User Project' (often inherited from a server template or Reference OS setup), causing WinCC to query ALM for a server license.

Can remote OS Clients connect to an OS Single Station?

No. An OS Single Station is licensed strictly for local operation; connecting remote OS Clients requires an OS Server multi-user license.

Will changing from Multi-User to Single-User delete my process graphics?

No. Graphics pictures (.pdl), tags, scripts, and alarm configurations remain 100% intact; only multi-user client routing configurations are deactivated.