Fixing STEP 7 V5.6 HW Config Not Opening on Windows 10

Problem Overview

STEP 7 V5.6 Professional with Hotfix 5 (HF5) running on Windows 10 64-bit (build 1909) fails to launch the HW Config editor. The symptom is silent: SIMATIC Manager opens, project navigation works, but selecting a hardware station and invoking Open HW Config produces no visible window, no dialog, and no logged error. The executable S7HCOMBX.exe (HW Config) appears in the process tree briefly and exits without an exception prompt.

This failure mode also affects adjacent components:

• WinCC Flexible 2008 SP5: previously exhibited the identical behavior on the same workstation and was recovered by a Reset to factory state from the WinCC Flexible Start Center.
• PLCSim and S7-GRAPH: residual installations left after partial uninstall of STEP 7, indicating shared component corruption.

The root cause is typically one of three underlying defects: (1) a known STEP 7 V5.6 shell library incompatibility patched in Service Pack 2 Hotfix 3, (2) a per-user Windows profile whose %APPDATA%\Siemens\Automation\ cache is poisoned, or (3) a partial uninstall that left orphaned COM registrations pointing at missing S7HELP and S7CMMIME DLLs.

Affected Software Versions and Compatibility Matrix

The supported operating system baseline for STEP 7 V5.6 is Windows 7 SP1 (32/64-bit), Windows Server 2008 R2 SP1, and Windows 10 Pro/Enterprise 1607 through 1909. Builds 2004 and later fall outside the formal support matrix and require SP2 HF3 or later for stability.

Root Cause Analysis

Three failure paths converge on the same symptom. Diagnose all three before applying corrective action.

Path A: Shell-Extension Defect in HW Config Launcher

HW Config is hosted by S7HCOMBX.exe, which depends on the shell extension S7CMMIME.dll and the help bridge S7HELP.dll. A defect in the V5.6 pre-SP2 builds causes the launcher to block on an IPC handle created by S7WinCC.exe when WinCC Flexible is installed concurrently. The window is created in a hidden state, and the absence of a console window masks the underlying ERROR_ACCESS_DENIED (0x80070005).

The defect is corrected in V5.6 SP2 Hotfix 3. Apply this update first when the workstation hosts both STEP 7 and WinCC Flexible / WinCC (TIA Portal) components.

Path B: Per-User Profile Corruption

STEP 7 stores per-user state in %APPDATA%\Siemens\Automation\ and the registry hive HKCU\Software\Siemens\Automation\. When the per-user HW Config workspace file S7Hwcnfg.wsp is truncated (typically after an unexpected shutdown or a Windows Update reboot during an active session), the launcher reads an invalid stream header and silently exits without rendering the editor window.

The user-profile workaround is the strongest indicator: launching the same STEP 7 executable under a different Windows account succeeds because that account initializes a clean %APPDATA%.

Path C: Orphaned COM Registration After Partial Uninstall

When STEP 7 is uninstalled but PLCSim and S7-GRAPH remain, the Microsoft Installer leaves registry keys under HKCR\CLSID\{...}\InprocServer32 referencing S7HCOMBXPS.dll in C:\Program Files\Siemens\Automation\S7BIN\. If that directory is removed, the next attempt to launch HW Config fails with a missing DLL — but the failure is silent because the loader short-circuits before the STEP 7 exception handler is installed.

Diagnostic Procedure

1. Open Task Manager → Details and enable the Command line column.
2. Launch HW Config from SIMATIC Manager.
3. Confirm that S7HCOMBX.exe "<project-path>\<station>.s7" appears and disappears within 2 seconds.
4. Open Event Viewer → Windows Logs → Application and filter for Application Error events with source Application Error in the last 5 minutes.
5. Capture %LOCALAPPDATA%\Temp\SiemensAutomation.log if present.
6. Run procmon /AcceptEula and capture a 30-second boot trace filtered to S7HCOMBX.exe; look for NAME NOT FOUND on registry paths under HKCR\Siemens.*.

If S7HCOMBX.exe does not appear at all, the launcher itself is failing — proceed to Solution Path A. If S7HCOMBX.exe appears and disappears, the failure is downstream — proceed to Solution Path B.

Solution Path A: Update to STEP 7 V5.6 SP2 Hotfix 3

This is the canonical fix for the shell-extension defect and is the recommended first action on any V5.6 pre-SP2 workstation.

1. Download STEP 7 V5.6 SP2 from the Siemens Industry Online Support entry ID 109773842.
2. Verify the downloaded archive against the SHA-256 checksum published in the entry's Files tab.
3. Close all STEP 7 components and stop the SIMATIC WinCC OPC Server and S7TraceSrv services.
4. Run setup.exe from the SP2 archive as Administrator. Choose Modify installation if STEP 7 V5.6 is already installed.
5. After SP2 completes, apply Hotfix 3 from entry ID 109779992.
6. Reboot the workstation and verify the installed version via SIMATIC Manager → Help → About. The reported build must read K5.6.2.3 or later.

Solution Path B: Repair the Per-User Profile

Use this path when Path A does not resolve the launch failure, or when the diagnostic trace shows S7HCOMBX.exe exiting after start. This procedure is non-destructive; the corrupted cache is rebuilt automatically.

1. Close all Siemens applications.
2. Open regedit.exe as the affected user.
3. Export (right-click → Export) the key HKCU\Software\Siemens\Automation to %USERPROFILE%\Desktop\SiemensAutomationBackup.reg as a rollback safety net.
4. Delete the key HKCU\Software\Siemens\Automation\HWConfig\Workspace.
5. Delete the file %APPDATA%\Siemens\Automation\HWConfig\S7Hwcnfg.wsp.
6. Delete the file %APPDATA%\Siemens\Automation\Shared\LastUsedStations.xml.
7. Launch HW Config once with a project containing a single S7-300 or S7-400 station to recreate the workspace. Close SIMATIC Manager.
8. Verify the regenerated files exist and have non-zero size before declaring the fix complete.

If the failure persists across three different Windows user accounts on the same workstation, the defect is system-wide and the workstation should be re-imaged or moved to Path C.

Solution Path C: Clean Reinstallation

Use this path when orphaned PLCSim or S7-GRAPH installations coexist with STEP 7, or when the registry hive HKCR\Siemens.* is corrupt.

1. Open Control Panel → Programs and Features and note every Siemens-Automation entry and its exact version.
2. Capture the list to %USERPROFILE%\Desktop\SiemensInventory.txt for reinstallation reference.
3. Uninstall in reverse-dependency order: S7-PLCSim, S7-GRAPH, S7-SCL, S7-PCT, then STEP 7. WinCC Flexible and WinCC (TIA Portal) should be uninstalled only if you no longer require them.
4. Reboot. Verify that C:\Program Files\Siemens\Automation\ is empty or absent.
5. Delete the residual folders manually: C:\Program Files (x86)\Siemens\, C:\ProgramData\Siemens\, and %PROGRAMDATA%\Siemens\Automation\.
6. Run MicrosoftProgram_Install_and_Uninstall.meta_diagcab (the official Microsoft Program Install and Uninstall Troubleshooter) to clear orphaned MSI references if Control Panel still shows the old entries.
7. Wipe HKLM\SOFTWARE\Siemens\Automation and HKLM\SOFTWARE\Wow6432Node\Siemens\Automation after exporting them.
8. Install STEP 7 V5.6 SP2, then Hotfix 3, then the optional components (PLCSim, GRAPH, SCL) in dependency order.
9. Reboot and launch HW Config against a known-good project.

STEP 7 HW Config Settings Reference

The HW Config editor exposes several user-configurable settings that influence launch behavior and catalog rendering. Although the reference below targets TIA Portal V20, the conceptual settings map to the legacy V5.6 settings dialog at Options → Settings → Hardware configuration.

Reference documentation: Overview of settings for hardware configuration — TIA Portal V20.

Troubleshooting Matrix

Verification Procedure

1. Launch SIMATIC Manager as the original affected user.
2. Open a project containing an S7-300 station with at least one signal module (SM) configured.
3. Double-click the station object. HW Config must render within 5 seconds.
4. Open PLC → Module Information on the CPU. Verify module diagnostic data is readable.
5. Save the project and re-open it. HW Config must re-launch without prompting for catalog refresh.
6. Confirm Help → About reports STEP 7 V5.6.2.3 or later.
7. Run a project consistency check: PLC → Compile and Download Objects with all objects selected.

Preventive Recommendations

• Standardize on SP2 HF3: Maintain a single STEP 7 V5.6 build across the engineering fleet. Mixing HF5 and SP2 HF3 stations produces non-reproducible faults during joint commissioning.
• Avoid concurrent WinCC Flexible and STEP 7 patching: Apply STEP 7 SP updates only when no WinCC components are running, even on read-only sessions.
• Snapshot the user profile: Before installing a Windows feature update (e.g., 1909 → 20H2), capture %APPDATA%\Siemens\ and HKCU\Software\Siemens for rollback.
• Keep the GSD catalog on a local path: Network-share catalog paths interact poorly with HW Config launch and can mask the silent failure.
• Track HW Config launches: For shop-floor workstations, enable Process Monitor boot tracing for the first 60 seconds after login to capture silent launcher exits.

Related Siemens Support Entry

For a broader catalog of why STEP 7 projects, blocks, or HW Config fail to open — including file corruption, version-mismatch, and catalog-update scenarios — see Siemens support entry "Why can't you open projects, blocks or the HW Config at all" (Entry ID 22809379). This entry addresses read-only opening, version-mismatch warnings, and catalog-update failures that may present alongside the silent-launch failure documented here.