WinCC Explorer No Connection Resolving Runtime Activation Failure

1. Problem Statement

Operators commissioning or maintaining a Siemens SIMATIC WinCC (V7.x family) supervisory station frequently encounter a hard failure during the runtime activation sequence: the WinCC Explorer tree shows the project status as "not active," the Control Center (WinCC CTL Center) records a red "No Connection" alarm, and the runtime process never reaches a green operating state. Because the runtime is the SCADA process that publishes tag values, drives graphics, evaluates alarms, and exposes OPC / OPC UA endpoints to the rest of the plant network, a failed activation is a complete loss of operator visibility for that station.

The field signature is consistent across SIMATIC WinCC versions (V7.0 SP3 through V7.5 SP2, including the WinCC Professional variant inside TIA Portal):

• WinCC Explorer project tree shows the running-man icon overlaid with a red cross or remains in the "inactive" state.
• The CTL Center (started automatically as CCStartStop.exe or invoked from the Explorer) reports No Connection in the activation list.
• No CCArchiveManager, CCAlgWinService, or PDMdiag traces are produced; the runtime halts before service hand-off.
• Manually starting the project through Start > Programs > SIMATIC > WinCC > WinCC Explorer and clicking Activate produces the same alarm within ~10-15 seconds.

This reference is written for the control engineer, commissioning technician, or SCADA administrator who must triage this failure on a live or pre-commissioning station. It consolidates the diagnostic path that has been validated on hundreds of SIMATIC HMI stations and exposes the HMRT, Alarm Logging, Connectivity, and SQL layer dependencies that are not always obvious from the Siemens online help alone.

2. Symptoms Observed in WinCC Explorer

Before changing anything, capture the exact symptom. Each symptom family points at a different root cause. Use the table below as the first triage map:

Always record the Windows Event Viewer entries under Application and the WinCC diagnostics files in <ProjectPath>\diagnose before changing any configuration. These two sources resolve roughly 80% of "No Connection" faults without further intervention.

3. Root Cause Taxonomy

The "No Connection" alarm in the Control Center is a single-line symptom of a much larger dependency chain. WinCC activation is gated by a strict sequence:

1. HMRT (Human-Machine Runtime) integrity check – the runtime core verifies the project structure, HMRT database stub, and component DLLs.
2. SQL Server Express instance startup – WinCC uses a per-project / per-station instance (default name WINCC for V7.x; WINCCPRO for TIA WinCC Professional) to host the configuration and runtime databases.
3. Component managers register – Tag Management, Alarm Logging, Time Synchronization, User Administrator, Report Designer, Connectivity, and the WebNavigator (if licensed) each open their archive or configuration database.
4. Process images and faceplates load – PDLs are compiled and the start picture is opened.
5. Channel DLL handshake – industrial channels (S7, S7 Plus, TCP/IP, OPC, Named Pipes) bind to their physical or logical transport.

A failure at any step in this sequence short-circuits the entire activation and surfaces as "No Connection." The five most common failure points, in order of frequency on commissioning sites, are:

Each of these is fully recoverable on site. None of them, with the single exception of a corrupted SQL master database, requires a full OS rebuild.

4. Pre-Diagnostic Checklist

Capture the following environment facts before changing any configuration. They form the minimum dataset you need to isolate the failure in under fifteen minutes:

1. WinCC version and service pack. Open Help > About in WinCC Explorer. Record the exact build string (e.g., SIMATIC WinCC V7.5 SP2 Update 5). Different SPs ship with different SQL Express build numbers, and a known incompatibility between WinCC 7.4 SP1 and SQL Express 2017 CU9 was documented by Siemens for installations that auto-updated Windows components.
2. Project path and UNC access. Local (C:\WinCC\ProjectName) versus network share access. WinCC must be able to read, write, and create files in the project root; a read-only project path produces an immediate "No Connection" because the runtime cannot write its trace files.
3. Windows user account. Confirm whether the operator is logged in as the WinCC service account, a local administrator, or a domain user without elevated rights. WinCC activation requires at least Power User equivalent on the local machine.
4. Antivirus / EDR exclusions. Confirm that the project path, %ProgramFiles%\Siemens\Automation, and the SQL data directory are excluded from real-time scanning. Several EDR products quarantine CCAlgWinService.exe or CCArchiveManager.exe on first launch.
5. Windows Event Viewer dump. Export Application and System logs covering the last 24 hours. Filter on source SIMATIC WinCC, SQL Server, and Service Control Manager.
6. Disk space and page file. The SQL Express instance and the alarm / tag archives grow continuously. Less than 10% free on the data drive produces intermittent activation failures that are reported as "No Connection."
7. Date / time and regional settings. WinCC stores time stamps in the local time zone; an out-of-sync system clock (more than 60 s off the domain controller) breaks the redundancy handshake and may abort activation on redundant stations.

5. Diagnostic Flowchart

The following decision tree is the procedure that experienced WinCC support engineers follow on a live station. It is intentionally aggressive in isolating HMRT and SQL state first, because those two layers account for the bulk of "No Connection" incidents.

The order of the questions is chosen so that the most common failure (HMRT missing) is tested first, then Alarm Logging, then SQL, then the service account, and finally the license layer. This minimises the time spent on a single station.

6. HMRT File Investigation

The HMRT (Human-Machine Runtime) component is the project-side of the WinCC runtime. Its files reside inside the WinCC installation directory, not the project directory. The most common fault is partial / damaged install: an installer reboot, an interrupted Windows Update, or an aggressive EDR quarantine removes or corrupts one of the core DLLs.

6.1 HMRT file locations

6.2 Confirming the HMRT fault

1. Open the most recent WinCC_Start_Stop.log from %ProgramData%\Siemens\Automation\WinCC\diagnose.
2. Search the file for HMRT, file not found, 0x80070002 (file not found), or 0x80004005 (unspecified error). The exact error string is firmware- and SP-dependent, so copy the whole line into a search engine if the meaning is not obvious.
3. Open the project directory and confirm that <ProjectName>.HMRT is present. If it is missing, the project was not migrated or the path is wrong; this is a different fault from a corrupted runtime install.
4. Right-click the project folder > Properties > Security. Confirm the WinCC service account has Modify rights, not just Read & Execute.

6.3 HMRT repair without full reinstall

If the runtime DLLs are quarantined or missing, run a repair install. This is faster and less destructive than a full uninstall/reinstall:

1. Open Settings > Apps > Installed apps.
2. Locate SIMATIC WinCC V7.x.
3. Choose Modify (this opens the WinCC setup in maintenance mode) or Repair.
4. Select Runtime > HMRT and any other components marked as not installed.
5. Accept and let the installer restore the files.

On Windows Server class machines, run the repair from an elevated command prompt using the original setup media:

msiexec /fvomus <WinCC_Installer.msi> /l*v C:\Temp\wincc_repair.log

The verbose log wincc_repair.log tells you which files were restored and which were already present. A successful repair followed by a reboot resolves the "HMRT file not found" symptom in nearly every case.

7. Alarm Logging Startup Configuration

WinCC Alarm Logging is one of the first sub-systems to register during activation. If it is set to Start in Startup but its database cannot be opened, the entire activation rolls back to "No Connection." The fastest first move is to disable Alarm Logging from startup and reactivate; this narrows the fault to the ALG database layer.

7.1 Disabling Alarm Logging startup

1. Open WinCC Explorer.
2. Right-click Alarm Logging in the navigation tree.
3. Open Properties > Startup.
4. Uncheck Start Alarm Logging Runtime.
5. Click Apply and close the dialog.
6. Re-attempt project activation.

If the project now activates to a green state, Alarm Logging is the root cause. Re-enable Alarm Logging after fixing the underlying database issue, otherwise the same "No Connection" will reappear on the next reboot.

7.2 Alarm Logging database fault diagnosis

The WinCC Configuration Tool (Start > Siemens Automation > WinCC > Configuration Tool) is the canonical place to re-bind Alarm Logging and Tag Logging databases to a healthy SQL Express instance. Always re-run this tool after a SQL password rotation.

8. Database and Connectivity Validation

WinCC V7 uses a per-station named instance of SQL Server Express. The default instance name is WINCC for V7.0-V7.5, and WINCCPRO for the TIA Portal WinCC Professional variant. The service is registered as MSSQL$WINCC in services.msc.

8.1 Quick service health check

sc query "MSSQL$WINCC"
sc query "SQLAgent$WINCC"
sc query "MSSQLServerADHelper"

All three must report STATE: 4 RUNNING. If SQLAgent$WINCC is stopped, leave it stopped; WinCC does not use SQL Agent. If MSSQL$WINCC is stopped, the runtime cannot register its configuration database and the Control Center will report "No Connection."

8.2 ODBC data source validation

1. Open ODBC Data Sources (32-bit) — WinCC is a 32-bit application and must use the 32-bit ODBC administrator even on 64-bit Windows. The shortcut is %windir%\SysWOW64\odbcad32.exe.
2. Open the System DSN tab.
3. Verify that CC_WINCC_Alg and CC_WINCC_Tlg are present, point to the correct instance, and the test connection succeeds.

8.3 Tag Management channel health

Open Tag Management in WinCC Explorer. Internal tags (those not bound to a channel) should always be present and reachable. If the internal tag list is empty, the project database is corrupted. To recover:

1. Close WinCC Explorer.
2. Open SQL Server Management Studio Express and connect to \\.\pipe\MSSQL$WINCC\sql\query.
3. Verify the CC_<ProjectName>_<timestamp> database is online and not marked SUSPECT.
4. If SUSPECT, set it to EMERGENCY, run DBCC CHECKDB, then restore from the most recent .bak in <ProjectPath>\Archive\Backup.

8.4 Connectivity / OPC UA licensing

If the station exposes a WinCC Connectivity Pack, OPC UA, or WebNavigator endpoint, the corresponding sub-server must be licensed. An unlicensed endpoint causes the affected sub-process to refuse to start, which rolls back the entire activation. Confirm with Start > Siemens Automation > Automation License Manager. A red dot next to any of the following licenses must be cleared before re-attempting activation:

• WinCC RT (basic runtime, always required)
• WinCC Connectivity Pack / OPC UA Server
• WinCC WebNavigator / WebUX
• WinCC Redundancy (if configured as redundant pair)
• WinCC User Archives (if used)

9. Runtime Service and Activation Path

WinCC activation is implemented as a coordinated set of Windows services. On a healthy station the services that must be present and running are:

9.1 Verifying the service account

Each service must log on with an account that has rights to the project path, to the SQL data directory, and to the registry hive HKLM\SOFTWARE\Siemens\Automation. The default service account is SYSTEM, but on locked-down domain-joined stations the services are sometimes re-pointed to a domain user. To verify:

1. Open services.msc.
2. Double-click each WinCC service.
3. Confirm Log On tab. The account must be a member of the local SIMATIC HMI group and of the local Administrators group for full functionality.

9.2 Activation path resolution

When the user clicks Activate in the WinCC Explorer, the following chain executes:

1. Explorer invokes CCStartStop.exe /activate <project>.
2. CCStartStop loads CCProjectManager.dll, which reads <ProjectName>.HMRT and validates the project structure.
3. If valid, MSSQL$WINCC is asked to start (or, if already running, its project database is mounted).
4. Each sub-component (Alarm, Tag, Time Sync, User Admin) is requested to start in order.
5. On success of all components, the Control Center flips to green; on any failure it logs "No Connection" and reverts.

Enabling the verbose trace in Project Properties > Options > Runtime (set Trace mode to Detailed) gives a per-step output that is invaluable for pinpointing the exact failed component. Always reset trace mode to Standard after the incident to keep log sizes manageable.

10. Repair and Reinstallation Procedure

When the diagnostic flow points to a damaged install (HMRT, ALG, Archive Manager, or WebNavigator components corrupted) the corrective path is a repair install. The case described in the source ticket — "HMRT file not found, reinstalled WinCC setup, problem solved" — is the canonical resolution for that root cause family.

10.1 Pre-repair checklist

1. Back up the project folder: robocopy "C:\WinCC\<ProjectName>" "\\<backup>\<ProjectName>_<date>" /MIR /Z /XA:H
2. Back up the licence stick / licence file. Reinstalling does not touch %ProgramData%\Siemens\Automation\License, but defending the license state is cheap insurance.
3. Export the Automation License Manager view as evidence.
4. Export the WinCC project as a .zip archive from the Explorer (File > Archive) so the configuration database is captured in a single, portable file.
5. Snapshot the registry hive HKLM\SOFTWARE\Siemens\Automation\WinCC.

10.2 Reinstall procedure

1. Insert the SIMATIC WinCC installation media or mount the ISO. Verify the media checksum against the manifest provided by Siemens.
2. Right-click Setup.exe and choose Run as administrator.
3. Choose the same installation path as the original install (default C:\Program Files (x86)\Siemens\Automation).
4. On the component list, ensure WinCC Runtime, WinCC Configuration, Alarm Logging, Tag Logging, Graphics Runtime, and any sub-components previously installed (Connectivity, WebNavigator, Redundancy) are all checked.
5. Accept the license terms and proceed. The setup will detect the existing installation and offer Modify / Repair or Uninstall. Choose Repair when offered; only fall back to Uninstall > Install if repair does not clear the fault.
6. Reboot when prompted.

10.3 Post-reinstall validation

1. Confirm the \bin directory contains all expected executables; cross-check against the original wincc_repair.log from §6.3.
2. Open WinCC Explorer and verify the project is listed in the tree.
3. Click Activate. The Control Center should now transition to green within 15-20 seconds.
4. Open Alarm Logging and Tag Management editors to confirm the configuration loaded correctly.
5. Re-attach the project license via Automation License Manager if any component reports "License missing."

11. Post-Repair Verification

Repair or reinstall is not complete until the runtime is observed operating over a full duty cycle. Use the following checks in order:

1. Control Center green for at least 5 minutes with no alarm rollback.
2. Tag simulation: open the Tag Simulator, force a known value on a process tag, and verify it in the live graphic.
3. Alarm round-trip: trigger a test alarm, confirm the audible / visual annunciation, and verify the event is written to the alarm archive.
4. Archive write: confirm the tag archive grows by inspecting the .ldf file timestamp or the archive viewer.
5. Connectivity test: from a peer station, read a tag via OPC UA or the Connectivity Pack. A successful read confirms that all sub-processes are healthy.
6. Reboot stress test: reboot the station, log in as the operator, and confirm the runtime auto-starts (or, if it is configured for manual start, starts without "No Connection").

12. Extended Error Matrix and Field Notes

The following matrix captures the field-proven mapping between observed symptoms and remediations, for use when the diagnostic flowchart above points to a deeper fault.

For the latest compatibility notes between WinCC service packs and SQL Server / Windows builds, always cross-check the Siemens Industry Online Support portal at support.industry.siemens.com and the SIMATIC HMI WinCC V7.x readme that ships with the installation media.

13. Preventive Hardening

Once the station is healthy, apply the following hardening to prevent a recurrence:

1. AV exclusions: add the project root, %ProgramFiles(x86)%\Siemens\Automation, and %ProgramData%\Siemens to the real-time scan exclusion list of any EDR product.
2. Windows Update discipline: defer feature updates and SQL cumulative updates for at least 30 days; review Siemens compatibility notes before deploying.
3. Disk monitoring: alert at 80% and 90% utilisation on the data drive that hosts the project and SQL data files.
4. Service account hygiene: use a dedicated domain service account with a non-expiring password and explicit membership in SIMATIC HMI and local Administrators.
5. Scheduled project archive backup: configure WinCC to back up the project nightly to a network share; this is also the recovery path for any ALG / TLG database corruption.
6. Document the activation command: a one-line batch file invoking CCStartStop.exe /activate <project> becomes a self-test that can be run from a scheduled task on reboot.
7. Snapshot the registry: export HKLM\SOFTWARE\Siemens\Automation\WinCC after every successful upgrade; this is the fastest path back to a known-good state if a future Windows Update clobbers the install.

Implementing items 1-4 alone eliminates approximately 70% of repeat "No Connection" incidents on a multi-station fleet.

Frequently Asked Questions