Resolving WinCC Service Project User Rights and Windows Password Change Errors on PCS 7 Engineering Stations

In SIMATIC PCS 7, changing the Windows user account password on an Engineering Station (ES) causes WinCC project opening to fail with the error 'User of service project is not available, not member of SIMATIC HMI or has not entered the correct password'. This occurs because WinCC Service Projects cache encrypted operating credentials in project settings and SQL database configurations. To resolve this: open WinCC Explorer directly (bypassing SIMATIC Manager), acknowledge the prompt to 'Fix user problem' or 'Adapt project user rights', navigate to 'Project Properties -> Options -> Service', enter the updated Windows password for the service user, and ensure the account remains in the local 'SIMATIC HMI' and 'SIMATIC NET' Windows user groups.

Executive Summary

Process automation systems adhering to corporate IT cybersecurity policies mandate regular password changes for Windows local and domain user accounts. On SIMATIC PCS 7 Engineering Stations (ES) and OS Single Stations, changing the Windows account password frequently paralyzes engineering operations. Engineers attempting to open the WinCC project from SIMATIC Manager are locked out by security exceptions citing user availability or SIMATIC HMI group membership. The breakdown occurs because WinCC stores service authentication tokens in project configuration files that do not update automatically when Windows credentials change. This guide explains the security mechanics and outlines the step-by-step restoration workflow.

Architecture and Fundamental Mechanics

SIMATIC WinCC operates under two distinct runtime models:
1. Standard Project: Runs interactively within the logged-on user's desktop session. Background processes inherit desktop session privileges.
2. Service Project: Runs WinCC Runtime as a Windows service in Session 0 without requiring an interactive user desktop logon. This mode is standard for dedicated servers and unmanned single stations.

When a WinCC project is defined as a Service Project (or inherits service rights during creation), WinCC encrypts and stores the designated service user's Windows credentials within project configuration files and SQL Server database tables (CC_<ProjectName>.mdf). Furthermore, the Windows Security Account Manager (SAM) validates database access against the local Windows user group SIMATIC HMI.

When the Windows password is changed, a credential mismatch occurs. When SIMATIC Manager attempts to launch WinCC via automation interfaces, WinCC detects that the cached password stored in the service project configuration no longer authenticates against Windows SAM. It halts execution, returning the ambiguous error: User of service project is not available, not member of SIMATIC HMI or has not entered the correct password.

Resolving this requires launching WinCC Explorer standalone, which invokes internal security recovery routines to prompt for the new password and update the encrypted service descriptor.

Step-by-Step Implementation Procedure

Launch WinCC Explorer Standalone:
a. Close SIMATIC Manager completely.
b. Open Windows Start menu and navigate to Siemens Automation -> SIMATIC -> WinCC -> WinCC Explorer.
c. In WinCC Explorer, select File -> Open and browse to the WinCC project file (.mcp) located in the project's wincproj folder.
Execute Automated User Rights Adaptation:
a. Upon opening, WinCC detects the credential mismatch and presents a prompt to 'Adapt project user rights' or 'Fix user problem'.
b. Click 'Yes' / 'OK' to allow WinCC to synchronize the active Windows user account with local database access rights.
Update Stored Password in Service Configuration:
a. In WinCC Explorer, right-click the project root in the navigation tree and select 'Properties'.
b. In the Project Properties window, switch to the 'Options' tab.
c. Under the 'Service' section, verify the configured Windows User Name.
d. Click 'Set Password' (or re-enter the password in the Password and Confirm Password fields) with the newly updated Windows password.
e. Click 'Apply' and 'OK'.
Verify Local Windows Group Memberships:
a. Open Windows Computer Management (compmgmt.msc) and navigate to Local Users and Groups -> Groups.
b. Double-click SIMATIC HMI and confirm the active Windows user account is a member.
c. Confirm membership in SIMATIC NET and the SQL Server instance user group.
d. If the user was missing, add the account and log off or restart the Windows operating system.
Re-open Project from SIMATIC Manager:
a. Close WinCC Explorer.
b. Launch SIMATIC Manager, open the multiproject, and open the WinCC OS project. The project opens cleanly without authorization errors.

Verification

Open the WinCC OS project directly from SIMATIC Manager: verify that WinCC Explorer loads all editors without displaying security exception dialogs.
In WinCC Explorer, select 'Tools -> Computer Information': confirm the active user displays valid administrative and SIMATIC HMI privileges.
Execute an OS delta compilation from SIMATIC Manager: verify the compilation connects to the WinCC SQL database and completes with 0 errors.
If configured as a service project, test runtime startup in service mode and verify that background processes initialize without logon failures.

Limitations and Operational Precautions

In Windows Workgroup environments, the identical username and password MUST be maintained on the Engineering Station and all target OS Servers to permit remote project downloads. If Windows accounts are managed by an Active Directory Domain Controller, group policy changes that restrict local user rights can revoke SIMATIC HMI memberships upon reboot, requiring domain administrator coordination.

Engineer FAQ

Why did the error claim I was not a member of SIMATIC HMI when I clearly was?

The error message combines three distinct failure modes: missing user, incorrect password, and missing group membership. An invalid password triggers this generic error string even when group membership is correct.

Can I convert a Service Project back to a Standard Project?

Yes. In WinCC Explorer, open Project Properties -> Options, and uncheck 'Service Project' (or set Operating Mode to Standard). This removes the background service credential requirement.

What utility can repair corrupted WinCC database user rights?

The Siemens utility CCSetSubProject.exe or Convert.exe can reset project user permissions and rebuild local SQL user mappings.

Does changing the Windows password affect remote OS downloading?

Yes. If the ES and target OS reside in a workgroup, the password on the target OS must be updated to match the ES password, or network share authentication (SMB) will fail.

Do domain user accounts require special permissions in PCS 7?

Yes. Domain accounts used for PCS 7 engineering must be added to the local SIMATIC HMI and SIMATIC NET groups on each engineering and operator station.