WinCC Professional V21: Fixing Parallel Install SQL Conflicts

Overview

Siemens SIMATIC WinCC Professional is a 64-bit SCADA/HMI engineering and runtime platform that ships inside the TIA Portal installation package. Each TIA Portal / WinCC release (V16, V17, V18, V19, V20, V21) is bound to a specific SQL Server database instance that stores the project archive, runtime archive, alarms, tags, recipes, and user administration data. Because of that binding, the installation routine refuses to put two WinCC Professional ES (Engineering System) or two WinCC Professional RT (Runtime) versions on the same machine.

This article documents the technical reason for the block, the clean uninstall sequence required to upgrade from one WinCC Professional version to another, and the verification steps that confirm the new installation is healthy. It applies to WinCC Professional V17 through V21; the official parallel-installation rule for V21 is documented in the TIA Portal V21 installation manual and is consistent with the behavior of every WinCC Professional release since V14.

Why Parallel Installation of WinCC Professional Is Blocked

The installation bootstrapper enforces a hard mutex during setup. The mutex is keyed on three identifiers:

1. The TIA Portal portal version (e.g., V17, V18, V21).
2. The WinCC Professional component set (ES, RT, ES+RT).
3. The registered Microsoft SQL Server instance name (default: WINCCPLUS).

When you launch the setup of a new WinCC Professional version, the bootstrapper scans for any pre-existing WinCC Professional product of an earlier version. If it detects one, it aborts with a setup dialog such as "Parallel installation is not permitted. Please uninstall the existing version first."

According to the TIA Portal V21 Parallel Installation documentation:

"Parallel installation of WinCC Professional V21 (ES or RT) with an earlier version of WinCC Professional (ES or RT) is not permitted."

The same rule applied to V17, V18, V19, and V20. The technical justification is the SQL Server instance binding described in the next section.

Root Cause: SQL Server Instance Binding

WinCC Professional uses a named instance of Microsoft SQL Server (or SQL Server Express) to persist runtime data. The instance is created during the WinCC Professional setup and is named according to the role of the installation.

Because every WinCC Professional version registers the same default instance name (WINCCPLUS), running two versions side-by-side would create:

• Service name collision: The Windows Service Control Manager only allows one service named SQL Server (WINCCPLUS). The second installation would either fail to register the service or silently overwrite the binary paths of the first.
• Database schema mismatch: Each WinCC Professional release ships its own schema version for the project database, archive database, and user database. A V21 service cannot read a V17 schema, and a V17 service cannot write a V21 schema. Cross-version access corrupts both.
• Registry key collision: The WinCC Professional configuration store under HKLM\SOFTWARE\Siemens\Automation and the SQL Server registry under HKLM\SOFTWARE\Microsoft\Microsoft SQL Server are version-pinned. A second install overwrites the first.
• File-system collision: Common program-data directories such as %ProgramData%\Siemens\Automation\WinCCProfessional are shared, so runtime archives and project caches would mix.

The WinCC Classic line (WinCC V7.0, 7.2, 7.3, 7.4, 7.5) is excluded for the same reason: it installs its own WinCC SQL instance and uses a different file layout.

Identifying the Active SQL Server Instance

Before any uninstall, enumerate every SQL Server instance present on the engineering or runtime PC. Use one of the following methods.

Method 1: Windows Services Applet

1. Open services.msc as Administrator.
2. Sort by name and look for entries starting with SQL Server (.
3. Record every instance name and its associated WinCC version. Typical values: WINCCPLUS, WINCCPLUSMIG, WinCC (WinCC V7.x).

Method 2: SQL Server Configuration Manager

1. Launch SQL Server Configuration Manager from the Start menu.
2. Expand SQL Server Services. Every installed SQL instance is listed with its service state (Running / Stopped).
3. Right-click an instance, choose Properties, and confirm the Binary Path. If the path contains ...\Microsoft SQL Server\MSSQL<n>.<x>\MSSQL\Binn\sqlservr.exe" -sWINCCPLUS, that instance is bound to WinCC Professional.

Method 3: Registry Inspection

1. Open regedit and navigate to HKLM\SOFTWARE\Microsoft\Microsoft SQL Server\Instance Names\SQL.
2. Each value under this key is an installed instance name (e.g., WINCCPLUS).
3. Cross-reference each value with the corresponding HKLM\SOFTWARE\Microsoft\Microsoft SQL Server\<InstanceName>\Setup entry to read the SQL Server version and the install path.

Method 4: Command Line

sqlcmd -L
sc query | findstr /I "MSSQL"
reg query "HKLM\SOFTWARE\Microsoft\Microsoft SQL Server\Instance Names\SQL" /s

The output lists every named instance visible on the machine. Any instance that is not the target WinCC Professional instance must be evaluated: if it belongs to a foreign application, leave it alone; if it belongs to the WinCC Professional version being removed, it must be uninstalled.

Pre-Migration Checklist

Execute these steps before launching any uninstall routine. Skipping a step risks losing runtime data.

1. Archive the WinCC Professional project. Open the existing project in TIA Portal and run Project > Archive. Save the .zap archive to a network share that is not on the affected PC.
2. Export runtime data. For WinCC Runtime Professional, export the alarm logs, tag logs, and audit trails via WinCC Explorer > Data Management > Export. The native SQL Server tables are dbo.ALG, dbo.TLG, and dbo.ASB.
3. Back up the SQL databases. Use SQL Server Management Studio (SSMS) connected to localhost\WINCCPLUS to back up every database except the system DBs. Default DB names: CC_PM_<ProjectName>, CC_RT_<ProjectName>, CC_ALG_<ProjectName>, CC_TLG_<ProjectName>.
4. Document user administration. Export the WinCC user list via WinCC Explorer > User Administration > Export. The export is a CSV that can be re-imported on the new version.
5. Stop every related Windows service. In services.msc, stop SIMATIC WinCC Professional, S7DOS Help Service, SQL Server (WINCCPLUS), and SQL Server Agent (WINCCPLUS).
6. Capture license keys. Use Siemens Automation License Manager to record the license ticket for WinCC Professional. The keys are machine-bound and survive a clean uninstall, but recording them avoids a panic call to support.

Uninstall Procedure: WinCC Professional ES and RT

The uninstall must run in this specific order. Reversing the order leaves the SQL instance orphaned and the next install will fail.

Step 1: Uninstall WinCC Professional via Control Panel

1. Open Settings > Apps > Installed apps.
2. Find every entry that begins with SIMATIC WinCC Professional (ES) or SIMATIC WinCC Runtime Professional (RT).
3. Click Uninstall, then Yes when UAC prompts.
4. Repeat for the matching TIA Portal entry (e.g., SIMATIC STEP 7 Professional V17) if no other TIA Portal version is to remain on the machine.

Step 2: Run the TIA Portal Cleanup Tool

1. Insert the original TIA Portal installation media or mount the ISO that contains the legacy version.
2. Navigate to the Support directory and launch Siemens_TIA_Portal_Cleanup.exe (or TIAPortalCleaner.exe for older media).
3. Select WinCC Professional and accept the default cleanup scope.
4. Reboot when prompted. The cleanup tool removes residual registry keys under HKLM\SOFTWARE\Siemens and orphaned folders under %ProgramFiles%\Siemens.

Removing the SQL Server Instance

If only the WinCC Professional product is uninstalled but the SQL instance WINCCPLUS remains, the new install will detect the existing instance and either fail or attempt a repair that may corrupt the new database. The dedicated Siemens FAQ titled "How do you uninstall a SIMATIC WinCC Professional or a SIMATIC WinCC Runtime Professional SQL Server Instance?" covers this exact scenario.

Method A: Programs and Features

1. Open Programs and Features (appwiz.cpl).
2. Look for entries named Microsoft SQL Server 2019 (64-bit) with the instance ID WINCCPLUS in parentheses, or Microsoft SQL Server 2019 Express similarly tagged.
3. Select the entry and click Uninstall/Change.
4. When prompted, choose Remove and pick the specific WINCCPLUS instance.
5. Reboot when the SQL uninstall completes.

Method B: Silent Removal with setup.exe

Locate the SQL Server setup media bundled with TIA Portal (usually under Support\SQL\<version>\setup.exe) and run:

setup.exe /Action=Uninstall /FEATURES=SQL,AS,RS,IS,Tools /INSTANCENAME=WINCCPLUS /Q

The /Q switch runs the removal silently. Append /IAcceptSQLServerLicenseTerms when invoking setup interactively to bypass the prompt; the silent switch already accepts the current EULA.

Method C: Manual Removal (Last Resort)

If the SQL Server uninstall fails or the entry has already been removed from Programs and Features, the instance can be erased manually. This must be the final option; an error here can destabilize the OS.

1. Delete the instance registry key: HKLM\SOFTWARE\Microsoft\Microsoft SQL Server\WINCCPLUS.
2. Delete the entry under HKLM\SOFTWARE\Microsoft\Microsoft SQL Server\Instance Names\SQL\WINCCPLUS.
3. Stop and delete the services MSSQL$WINCCPLUS and SQLAgent$WINCCPLUS via sc delete MSSQL$WINCCPLUS and sc delete SQLAgent$WINCCPLUS.
4. Delete the data directory C:\Program Files\Microsoft SQL Server\MSSQL<n>.WINCCPLUS\.
5. Remove the leftover folder %ProgramData%\Microsoft\Microsoft SQL Server\WINCCPLUS.

Installing the Target Version

With the old ES, RT, and SQL instance fully removed, install the target WinCC Professional release.

1. Disable antivirus real-time scanning temporarily; TIA Portal setups are large and AV hooks slow them dramatically.
2. Mount the TIA Portal Vxx ISO and run Start.exe as Administrator.
3. Choose Install > User-defined installation and tick the WinCC Professional ES and/or RT components.
4. Accept the default SQL instance name (WINCCPLUS). Do not change it; downstream WinCC clients expect that exact name.
5. When the setup offers to install Microsoft SQL Server, accept. The bundled Express edition is sufficient for projects under 2 GB of archive data; for larger projects install the full SQL Server from the same media.
6. After setup finishes, reboot and run Siemens Automation License Manager to move the existing license ticket onto the new version.

Verifying the New Installation

Run the following checks before signing off the migration.

Troubleshooting Common Errors

Best Practices and Alternate Strategies

For production fleets where multiple TIA Portal versions must be supported simultaneously, the single-PC limit can be sidestepped with one of the following architectures:

• Virtual machines: Run one WinCC Professional version per VM. This is the official workaround when a customer must maintain engineering stations for both V17 and V21.
• Dedicated engineering PCs: Maintain one physical machine per major TIA Portal version. Best for long-running project lifecycles where recompiling against a new WinCC version is risky.
• Containerized WinCC Professional RT: Since V19, WinCC Runtime Professional is officially supported on Windows Server containers with Hyper-V isolation. Each container hosts its own WINCCPLUS instance in isolation.
• Central archive server: Run WinCC Runtime Professional RT on one PC and point multiple ES workstations at it via the SQL Server network configuration. This isolates the SQL instance to one machine and avoids the parallel-install problem on the ES.

FAQ