Resolving WinCC RT vs RC License Conflict on PCS7 Client PCs

A frequent fault mode in PCS 7 plants using WinCC Runtime/Configuration is the silent failure of the configuration interface on operator stations after a license is added or transferred. The symptom is straightforward: WinCC Explorer opens in read-only mode, the Graphics Designer is greyed out, project editing returns an error, and no alarm is raised by the OS. The cause is almost always a parallel install of an RT (Runtime) and an RC (Runtime + Configuration) license on the same client. This article documents the field-proven diagnosis, the corrective action through Automation License Manager (ALM), and the commissioning-time checks that prevent recurrence.

1. Problem Scope and Environment

The reference installation is a PCS 7 V8.2 / V9.0 SP2 / V9.1 multi-station system:

• 2 x AS pair (AS 410 / AS 410-H redundant)
• 2 x WinCC Server (OS Server 1, OS Server 2) with Server redundancy
• 10 x WinCC Clients (OS Clients) running WinCC Runtime on Windows 10 LTSC 2019 / Windows Server 2016
• 1 x Engineering Station (ES) with SIMATIC PCS 7 / STEP 7 / WinCC Explorer

License fault signature: 3 of 10 clients open the project in runtime correctly but cannot open WinCC Explorer for online configuration. The other 7 operate without issue. The license view in ALM shows both an RT license and an RC license present on the affected clients. The RT license is normally checked first; therefore the RC license is never used.

2. WinCC License Type Reference

PCS 7 ships a tiered set of WinCC licenses. Each tier grants a different set of rights. Mixing tiers on the same station is the most common cause of the fault described here.

For an authoritative description of each license scope, refer to the SIMATIC PCS 7 License Overview (Entry ID 109769309) and the WinCC/PCS 7 License Quick Reference (Entry ID 109771707).

3. Root Cause: License Search Order

When the WinCC Runtime/Configuration service (CCLicensing.exe / LicenseService.exe) starts, it queries the Automation License Manager through the Wibu-Systems CodeMeter runtime. ALM returns the first license that matches the requested license tag. The search order is determined by:

1. The container (local hard drive, USB dongle, network dongle server) registered earliest in ALM.
2. The position of the license within the container (firmware slot 1-50).
3. License tag priority (RT before RC, RC before ES, server before client).

If an RT license is found first, the licensing subsystem assumes the configuration rights are not required and stops searching for an RC license on the same machine, even if the RC license is technically present and not currently in use. This is by design; the runtime will not "promote" a station to configuration rights without an explicit license pick. The same rule applies to RC vs ES on the engineering station: a server-type license always wins.

Field observation: when both RT and RC exist in the same ALM container, LicenseLog.log shows a single line — License found: WinCC RT (Slot 03) — with no error and no warning. The RC license slot is treated as unallocated.

4. Pre-Diagnostics: Confirm the Fault

Before changing anything on the affected client, capture a diagnostic snapshot:

1. Open Automation License Manager from Start → Siemens Automation → Automation License Manager or the path C:\Program Files (x86)\Siemens\Automation\ALM\ALM.exe.
2. Switch to the affected client and select Connect → Local Computer.
3. List all licenses. The right pane shows: Container / Slot / License Tag / Type / Status / Expiration.
4. Check the Type column. If both RT and RC appear with status Valid, the conflict is confirmed.
5. Open the log file at C:\ProgramData\Siemens\Automation\Log\LicenseLog.xml (path may vary by PCS 7 version) and look for the last successful license acquisition line.
6. On the client, attempt to start WinCC Explorer from the OS project shortcut. If the project opens without prompting for a configuration password and the left tree is fully editable, RC rights are being honored. If the project opens but a banner reads "Operating in Runtime only mode" or the menu item Graphics Designer is greyed out, the RT license has won the search.

Document the slot numbers and license keys for the audit trail. PCS 7 audits require evidence of license state before and after maintenance windows.

5. Resolution: Remove or Relocate the Conflicting License

There are three field-proven remedies. Apply them in order of preference: relocate, transfer, or re-host.

5.1 Method A — Relocate the RT license to another container

If the RT license must remain on the client (the operator still needs runtime rights), the cleanest fix is to move the RC license to a different ALM container that is searched first.

1. Insert a USB license dongle (Wibu-Systems CmDongle / CmStick) into the client. ALM auto-detects it as a new container.
2. Open ALM, select the RC license entry, and drag it from the local hard drive container to the USB container.
3. ALM prompts for a fingerprint confirmation; accept.
4. Repeat the connection order so that the USB container is registered first (ALM honors registration order; re-insert if needed).
5. Restart the WinCC services: CCLicensing.exe /shutdown followed by CCLicensing.exe /start, or reboot the client.

The licensing subsystem will now find the RC license on the USB container and grant configuration rights. The internal hard drive container still holds the RT license for runtime fallback if the USB stick is removed during a maintenance window.

5.2 Method B — Remove the RT license entirely

If the station is a maintenance client that only operates in configuration mode, the RT license is redundant. Removing it eliminates the conflict.

1. In ALM, right-click the RT license and select Remove.
2. ALM returns the license to its original license certificate (the .zip / .WibuCmRaU file). The certificate is preserved in the C:\Program Files (x86)\Siemens\Automation\Certificates folder or the original USB distribution medium.
3. Reboot the client. WinCC Configuration will now activate.
4. Archive the license certificate on the central license storage share, e.g. \\PLANT-LIC\Siemens\WinCC\V9.0\.

5.3 Method C — Transfer via Automation License Manager (network)

For multi-client deployments, use ALM's network transfer to move the RT license from the three affected clients to a license server, and consolidate RC licenses on the affected machines.

1. On a designated license server (e.g. PLANT-LIC), install the Wibu-Systems CodeMeter Network License Server.
2. On each affected client, open ALM and connect to the license server.
3. Drag the RT license from the client's local container to the server container.
4. The RC license is now the only WinCC license on the client; restart WinCC.

Network licensing requires a stable network between client and license server. In PCS 7 plants with redundant ring topology, this is acceptable; in plants with a single uplink to the OS subnet, retain Method A or B to avoid runtime interruption during network events.

6. Migrating a License from a Legacy Floppy Disk

Older PCS 7 systems (V6.x / V7.0) were distributed on 3.5" floppy disks or parallel-port license dongles. Modern hardware has neither. The license certificate must be transferred.

1. Use a USB floppy drive (e.g. TDK / Sony USB FDD) on a 32-bit maintenance PC running Windows 7 / Windows 10 with the original ALM V5.x or V6.x installed. The legacy ALM can be downloaded from Siemens Support Entry 77373291.
2. Insert the floppy. ALM auto-reads the license certificate from the disk's root directory and registers it in the local container.
3. In ALM, select License → Export to a .zip certificate file. Save the file to a USB stick.
4. On the target client, install the current ALM version (V6.4 or later) and Import the .zip.
5. Verify the license is shown as Valid in the ALM tree.

If the floppy cannot be read at all, contact Siemens Technical Support for license restoration. Provide the original order number (MLFB), the certificate ID, and the host SID. The Siemens license team can reissue a license to a new .zip certificate tied to a new fingerprint.

7. Verification

After any license change, validate the result through this checklist:

1. ALM shows only the intended license tag (RT or RC) in the active container. The other tag is either absent or in a separate, unregistered container.
2. Open WinCC Explorer on the client. The left project tree is fully populated; Graphics Designer, Tag Management, and Alarm Logging are accessible.
3. Open a process picture, edit a button event (e.g. change a tag name), and save. The change persists in the project database.
4. Start WinCC Runtime. Process values update; no license error is written to LicenseLog.xml.
5. Check the CCLicensing service status: sc query CCLicensing should return STATE: 4 RUNNING.
6. Tail the event log: wevtutil qe Application /q:"*[System[(Provider[@Name='CCLicensing'])]]" /f:text /c:5 — no error 0x8000xxxx codes.

8. PCS 7 OS Client Configuration Rules

Three configuration rules must be enforced by the plant's automation team to prevent recurrence:

For projects with PCS 7 V9.1 and later, the PCS 7 V9.1 Installation Manual (Entry ID 109769765) recommends a single dedicated Backup / Engineering Client with only the RC license and no RT license. Operator stations should hold only the RT license. This eliminates the search-order issue by construction.

9. Field Engineering Notes

Three operational caveats from commissioning experience:

1. Antivirus interference. Some endpoint protection suites quarantine LicenseService.exe on first boot, leading to license acquisition failures. Add an exception for C:\Program Files (x86)\Siemens\Automation\ and the Wibu-Systems CodeMeter path C:\Program Files (x86)\WIBU-SYSTEMS\CodeMeter\.
2. Windows time skew. ALM validates time-based licenses against system time. A 5-minute skew between client and license server will cause intermittent license drops. Enforce NTP on the OS subnet.
3. User Account Control. License changes require local administrator rights. Log in with the dedicated PCS7Admin service account, not a personal domain user, so that audit trails remain consistent.

10. Diagnostic Flow Diagram

The following decision flow summarizes the diagnosis and remediation path:

11. Related Siemens Documentation

For deeper reading, the following Siemens Knowledge Base entries are the authoritative references used in field service:

• PCS 7 Licensing Overview (109769309)
• SIMATIC WinCC/PCS 7 License Quick Reference (109771707)
• Automation License Manager V6.4 Download (77373291)
• PCS 7 V9.1 Installation Manual (109769765)
• WinCC Configuration Rights and License Hierarchy (109750450)
• Wibu-Systems CodeMeter Runtime (Wibu-Systems)

12. Frequently Asked Questions