WinCC V6.2 SP2 SQL Server 2005 Configuration Fix Project Open

1. Overview: Why WinCC V6.2 SP2 Cannot Start Without the WinCC SQL Instance

Siemens WinCC V6.2 SP2 is the second service pack of the WinCC V6.2 SCADA/HMI runtime line. Internally, the WinCC archive database, the user administration database, the message and tag logging system, and the redundancy/partner-station configuration all rely on Microsoft SQL Server 2005 Express Edition bound to a fixed named instance. Unlike generic SQL Server 2005 installations, the runtime must use the instance that WinCC itself creates during its own setup routine. This requirement is documented in the Siemens Industry Online Support entry "Why can't you install the SQL server from WinCC V6.2?" (SIOS 30576253): the SQL Server 2005 Express can only be installed from the WinCC V6.2 / V6.2 SP2 setup media because only the WinCC setup provisions the correct instance name, the correct service accounts, and the matching SQL_Latin1_General_CP1_CI_AS collation expected by the WinCC project database.

If a workstation contains a stray SQL Server 2000 "WinCC" instance from a previous WinCC V6.0 installation, or if a developer tries to install WinCC V6.2 SP2 on top of a workstation that has a manually installed SQL Server 2005 with a different default instance (MSSQLSERVER), the WinCC setup will detect the conflict, abort, and the project will subsequently fail to open with one of the documented SQL connection error dialogs.

This article documents the correct install order, the required instance name, the registry keys that the WinCC setup writes, the exact error texts produced by the project-opener, and the field-proven procedure for repairing a broken SQL configuration without re-imaging the engineering station.

2. Product and Version Matrix

The dependency chain between WinCC and SQL Server is version-locked. Mixing the wrong components will produce the symptoms described later in the troubleshooting matrix.

3. Prerequisites

Before starting the install/repair procedure, verify the following on the engineering station:

1. Operating system: Windows XP Professional SP2/SP3, Windows Server 2003 SP1/SP2, or Windows XP Embedded (industrial PCs). WinCC V6.2 SP2 is not certified on Windows Vista or later; for those OS targets, upgrade to WinCC V7.0 or V7.0 SP1.
2. Administrator account: The setup must run under a local administrator or a domain account that is a member of the local Administrators group. The SQL service is installed to run as NTAUTHORITY\SYSTEM, but the WinCC setup writes registry and file-system ACLs that require elevation.
3. Disk space: Minimum 1.5 GB free on the system drive for WinCC plus the SQL Server 2005 Express payload; another 2 GB free on the data drive if tag logging archives are configured to a non-system location.
4. Pre-existing SQL instances: Verify that no MSSQLSERVER default instance from SQL Server 2005 is present, and that no WinCC instance from a previous SQL Server 2000 install is present. Open SQL Server Configuration Manager → SQL Server 2005 Services and inspect the right pane; the only SQL-related service that should be present after a clean install is SQL Server (WinCC) with start type Automatic.
5. WinCC V6.2 SP2 installation media: The full DVD or the licensed download from SIOS, including the SQL Server 2005 Express Edition (WinCC instance) component. The standalone Microsoft SQL Server 2005 Express redistributable does not contain the WinCC instance provisioning logic and will not satisfy the dependency.

4. Correct Installation Order

Siemens SIOS 30576253 explicitly states that the SQL Server must be installed from the WinCC V6.2 / V6.2 SP2 setup. The correct sequence is therefore:

1. Boot the engineering station. Confirm no other SQL Server 2005 instance is running.
2. Insert the WinCC V6.2 SP2 DVD (or mount the ISO).
3. Run Setup.exe from the DVD root. The setup detects the absence of a WinCC instance and prompts to install the prerequisite SQL Server 2005 Express Edition (WinCC).
4. Accept the prerequisite prompt. The setup provisions the WinCC named instance, applies the required collation, and sets the service account to Local System.
5. Continue the WinCC setup and select the components (WinCC Explorer, Graphics Designer, Tag Logging, Alarm Logging, User Administrator, etc.).
6. Reboot when prompted. The service SQL Server (WinCC) must be in state Running before the first WinCC Explorer launch.

5. SQL Server 2005 WinCC Instance Anatomy

After a clean WinCC V6.2 SP2 install, the following artifacts are created on the engineering station. Use this checklist to verify the install was successful before opening any project.

6. Documented Project-Open Error Dialogs

• Error 1001 / "Cannot load database DLL" — raised by the WinCC project opener when the OLE DB provider cannot connect to the WinCC instance. Typical cause: the SQL Server (WinCC) service is stopped, or the named-pipes protocol is disabled.
• "Connection to database WinCC failed" / "General SQL error" — raised by CCArchiveConn when the connection string Provider=MSOLEDBSQL;Data Source=localhost\WinCC;Initial Catalog=master;Integrated Security=SSPI; cannot authenticate. Typical cause: the SQL service is running as Network Service instead of Local System, or SPNs are missing in a domain environment.
• "The WinCC instance of MS SQL Server is not installed" — raised by the WinCC setup bootstrap when the prerequisite check fails because a non-WinCC SQL Server 2005 instance blocks the install. Resolved by removing the foreign instance.
• Event Viewer Application log: Event ID 18456, Severity 14, State 38 — "Login failed for user 'NT AUTHORITY\SYSTEM'. Reason: Failed to open the explicitly specified database." Typical cause: the database files for the WinCC project were created under a different service account in a prior install and the ACLs are no longer readable by SYSTEM.

7. Step-by-Step Repair Procedure

The following procedure restores a WinCC V6.2 SP2 station that opens projects with a SQL connection error. It is written to preserve any existing WinCC projects in C:\Program Files\Siemens\Automation\WinCC\WinCCProjects while repairing the SQL layer.

7.1 Stop the WinCC runtime and Explorer

1. Close WinCC Explorer and any open Graphics Designer / Tag Logging editor windows.
2. Open Services (services.msc) and stop the services in this order: SIMATIC WinCC Explorer → CCArchiveManager → SQL Server (WinCC).
3. Confirm the SQL Server (WinCC) service is in state Stopped.

7.2 Verify the SQL instance is the WinCC instance

1. Open a command prompt and run:
   sc query | findstr /I "sql"
2. The output must show exactly one service whose display name is SQL Server (WinCC). If any other SQL service is present, the system is contaminated; jump to Section 7.5 (Re-provision from WinCC setup).

7.3 Reset the SQL service to Local System

1. In Services, open SQL Server (WinCC) → Log On tab.
2. Select Built-in account: Local System. Click OK.
3. Do not enter a domain account here; WinCC V6.2 SP2 ships with Local System as the documented service account.

7.4 Reset database file ACLs

Database file ACLs sometimes become unreadable to SYSTEM after a backup/restore or after a manual copy of the data directory. Reset them as follows:

1. Open a command prompt as Administrator.
2. Run:
   icacls "C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\Data" /T /C /grant "NT AUTHORITY\SYSTEM:(OI)(CI)F" "BUILTIN\Administrators:(OI)(CI)F"
3. Confirm "Successfully processed X files; Failed processing 0 files."

7.5 Re-provision the SQL instance from the WinCC setup

1. Open Control Panel → Add/Remove Programs.
2. Select Siemens HMI WinCC V6.2 SP2 → Change.
3. In the WinCC setup dialog, select Modify and ensure the component MS SQL Server 2005 Express Edition (WinCC instance) is checked. If it is already checked, uncheck it, complete the modify to remove, then re-run the setup and check it again to re-install.
4. The setup re-installs the WinCC instance, registers the service, and rewrites the registry keys listed in Section 5.
5. Reboot the station.

7.6 Re-create the WinCC project databases

If a project still fails to open after Sections 7.1–7.5:

1. Open SQL Server Management Studio Express (installed by the WinCC setup as a separate component, SQL Server 2005 SSMSE).
2. Connect to localhost\WinCC with Windows Authentication.
3. Right-click Databases → New Database and create the three project databases expected by WinCC: CC_MAINT_<ProjectName>, CC_ALG_<ProjectName>, CC_TLG_<ProjectName> (WinCC will populate them on first runtime activation, but pre-creating them resets the ACLs to the LocalSystem owner).
4. Close SSMSE and re-open the WinCC project in WinCC Explorer.

8. Verification

After completing the repair procedure, verify the install in the following order. Each step must pass before moving to the next.

1. Service check: In services.msc, SQL Server (WinCC) is Started, Automatic, and logged on as Local System.
2. Port check: From a command prompt, run netstat -ano | findstr :1433. A line with state LISTENING must be present. (If a firewall blocks 1433 to localhost, WinCC still works locally; if WinCC is the OPC server for a remote client, port 1433 must be open between the two hosts.)
3. Connectivity check: In SSMSE, localhost\WinCC connects with Windows authentication. Run SELECT @@VERSION — expected return begins with Microsoft SQL Server 2005 - 9.00.xxxx.
4. Collation check: Run SELECT SERVERPROPERTY('Collation'). Expected return: SQL_Latin1_General_CP1_CI_AS.
5. Project open: Launch WinCC Explorer, open the project, and confirm the project tree loads without a SQL error dialog. Activate the project to Runtime; the Event Viewer Application log must contain no Event ID 18456 entries.
6. Archive write: In runtime, write a tag whose archive is enabled. Open the Tag Logging editor, view the archive, and confirm a row is written. This proves the WinCC-to-SQL write path is functional end-to-end.

9. Troubleshooting Matrix

10. Field-Proven Caveats

• Do not apply Windows service packs blindly. Windows XP SP3 and Server 2003 SP2 are tested; installing the SQL Server 2005 SP3 rollup on top of WinCC's bundled Express instance is supported, but applying SQL Server 2005 CU patches released after the WinCC CD cut-off can break the WinCC instance if the patch re-runs the upgrade script against the WinCC system DBs.
• Antivirus exclusion. Real-time AV scanning of the SQL data directory (C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\Data) and of the WinCC project directory degrades archive writes and may cause spurious Event ID 17055 errors. Exclude these paths in the AV policy.
• UAC on Windows XP Embedded. If the engineering station runs the Windows XP Embedded variant, confirm that the WinCC setup was launched with the Run as option, even though UAC is not present; this ensures the registry ACLs are written to the local Administrators group and not to a single user.
• Domain vs. local account. The WinCC V6.2 SP2 setup does not provision a domain account for the SQL service. If the station is later joined to a domain, re-validate the service account; never let a GPO override the SQL service logon.
• Port collision. A custom WinCC OPC server on TCP 1433 can conflict with the SQL listener. Change the WinCC SQL instance to a non-default port only if you have explicit Siemens approval, because WinCC's internal connection strings assume the default port.

11. When to Upgrade Instead of Repair

Repair is the right call when the SQL layer is intact but misconfigured, when the database files are recoverable, and when the engineering station runs a supported OS. Upgrade is the right call when:

• The workstation has been migrated to Windows 7 / Server 2008 R2 / later — WinCC V6.2 SP2 is not certified for those OS versions; move to WinCC V7.0 SP3 or WinCC V7.2 with their corresponding SQL Server 2008 / 2012 instances.
• The project exceeds 64,000 tags or 4,000 archived tags — WinCC V6.2 SP2 is a 64k-tag product; the licensed V6.2 SP2 PowerPacks lift the limit only on V6.2 SP2 itself, not on later versions.
• Long-term support is required. Siemens support for V6.2 SP2 ended in 2011; current SIOS entries for V6.2 are limited to legacy customer access.

12. Frequently Asked Questions