Fix SiemensHMI.TIA.HmiSRT.Vxx Not Registered Error in TIA Portal

Problem Overview

Engineers running the integrated HMI simulator in TIA Portal for a SIMIT-style or built-in KTP 1000 / Comfort Panel project encounter a blocking fault the moment they press the "Start simulation" button (or call StartRT from the HMI runtime). The WinCC RT loader reports:

SiemensHMI.TIA.HmiSRT.Vxx not registered

The same message appears in the Output window of the HMI device view and in C:\Users\<user>\AppData\Local\Siemens\Automation\Log\HmiSRT.log when tracing is enabled. The simulator returns a non-zero exit code and the panel does not come up, blocking all offline debugging.

This fault is independent of the project. It is a workstation-level problem: the COM/registry plumbing for the HMI Soft Real-Time (HmiSRT) service that backs the simulator is missing from the Windows registry.

Affected Products and Versions

The HmiSRT (HMI Soft Real-Time) module is a Windows service / COM server shared by every HMI target that uses the WinCC Advanced / Professional runtime simulator. A single missing registration breaks simulation for all HMI devices in the project tree, even those on different firmware lines.

Root Cause Analysis

HmiSRT is registered with the Windows registry on a normal TIA Portal install, but the entries are dropped, corrupted, or never written under any of the following conditions:

1. Elevated install blocked by UAC. TIA Portal was installed or patched without a full administrator token, so the per-machine COM registration was silently skipped.
2. Antivirus / EDR quarantine. Endpoint protection deletes or quarantines the freshly written registry keys after the installer exits (common with CrowdStrike, SentinelOne, and Defender ASR rules for unsigned .reg writes).
3. Repair / modify setup did not re-register. Running the Siemens setup in "Repair" mode on a user-level installer token leaves the COM keys missing while the binaries are intact.
4. Multi-version coexistence. Side-by-side installs of TIA V15 and V16 (or V17 over V16) overwrite each other's CLSID entries because both write to the same SiemensHMI.TIA.HmiSRT ProgID.
5. Corporate image / clone deployment. The OS image was captured before TIA finished its post-install COM registration, so the keys never exist on the deployed workstation.
6. Permission on HKLM\SOFTWARE\WOW6432Node\Siemens was stripped by a hardening GPO, blocking the installer from creating the key.

When the simulator launches, it queries the registry for the CLSID behind the SiemensHMI.TIA.HmiSRT.Vxx ProgID. If the CLSID is absent, CoCreateInstance returns REGDB_E_CLASSNOTREG (0x80040154) and the loader surfaces the human-readable message in the dialog.

Prerequisites

• Local administrator account on the engineering workstation.
• TIA Portal closed completely, including the TIA Administrator tray icon and any background S7OUCSAx.exe / HmiSRT.exe process. Verify with Task Manager.
• Path to the simulator folder for the active version. Replace V16 below with V14, V15_1, V17, or V18 as required:
  • C:\Program Files\Siemens\Automation\Portal V16\Win32\SmartSimulator
  • C:\Program Files\Siemens\Automation\Portal V16\Win64\SmartSimulator
• Read access to the registry hive HKEY_LOCAL_MACHINE and write access to HKLM\SOFTWARE\WOW6432Node\Siemens\Automation.
• If your shop uses a software restriction policy, temporarily exclude the SmartSimulator folder or grant the reg-file the appropriate SHA-256 hash rule.

Step-by-Step Resolution Procedure

1. Close TIA Portal. Right-click the TIA icon in the notification area and select Exit. Confirm with Task Manager that no Portal.exe, HmiSRT.exe, S7OUCSAx.exe, or Siemens.Automation.Portal.exe remain.
2. Open an elevated file browser. Press Win, type SmartSimulator, and click Open file location on the V16 entry. Or browse directly to C:\Program Files\Siemens\Automation\Portal V16\Win32\SmartSimulator in an Explorer window started with Run as administrator.
3. Locate the batch file. In the SmartSimulator folder you will see HmiSRTRegister_reg (file extension is .bat or .cmd). Right-click it and choose Run as administrator. Approve the UAC prompt.
4. Verify generation of the two registry files. The batch file writes two .reg files into the same directory:
   • HmiSRTreg.reg – 32-bit CLSID for the WoW HmiSRT server
   • HmiSRTreg_Vxx.reg – version-suffixed ProgID and AppID entries
   Confirm both files exist and are timestamped to the current second.
5. Import the registry files. Double-click HmiSRTreg.reg, accept the UAC prompt, and click Yes in the Registry Editor confirmation. Repeat for HmiSRTreg_Vxx.reg. Both files must be imported; the order is not significant.
6. Confirm the keys were written. Open regedit as administrator and check the following paths exist:
   • HKLM\SOFTWARE\Classes\SiemensHMI.TIA.HmiSRT.V16 with default value Siemens HMI Soft Real-Time V16
   • HKLM\SOFTWARE\Classes\CLSID\{<GUID>}\InprocServer32 pointing to HmiSRT.dll inside the SmartSimulator folder
   • HKLM\SOFTWARE\WOW6432Node\Siemens\Automation\Portal V16\HmiSRT with the install path string value
7. Restart TIA Portal as administrator. Right-click the TIA shortcut and choose Run as administrator for the first launch after the fix. Normal user rights will work on subsequent launches.
8. Retry the simulation. Open the HMI device, expand Online > Simulation > Start (or press the play button). The simulator window should appear within 5–10 seconds without the registration error.

Command-Line Alternative

When the graphical registry editor is unavailable, blocked by GPO, or you are scripting a fleet of workstations, use the unattended equivalent of the same procedure:

@echo off
setlocal
set TIAVER=V16
set ROOT="C:\Program Files\Siemens\Automation\Portal %TIAVER%\Win32\SmartSimulator"

:: 1. Stop any running HMI simulator
taskkill /F /IM HmiSRT.exe   2>NUL
taskkill /F /IM S7OUCSAx.exe 2>NUL

:: 2. Run the generator batch as admin (re-launch self with PSExec-style elevation if needed)
pushd %ROOT%
call HmiSRTRegister_reg.bat
popd

:: 3. Silently import the two .reg files
regedit /s "%ROOT%\HmiSRTreg.reg"
regedit /s "%ROOT%\HmiSRTreg_Vxx.reg"

:: 4. Verify the ProgID was created
reg query "HKLM\SOFTWARE\Classes\SiemensHMI.TIA.HmiSRT.%TIAVER%" >NUL 2>&1
if %ERRORLEVEL% NEQ 0 (
    echo FAILED: HmiSRT V%TIAVER% not registered
    exit /b 1
)
echo OK: HmiSRT V%TIAVER% registered
endlocal

For PowerShell deployments (Intune, MDT, or Ansible for Windows) the equivalent one-liner is:

$ver='V16'
$root="C:\Program Files\Siemens\Automation\Portal $ver\Win32\SmartSimulator"
Start-Process -Verb RunAs -FilePath "$root\HmiSRTRegister_reg.bat" -Wait
reg import "$root\HmiSRTreg.reg"        2>$null
reg import "$root\HmiSRTreg_Vxx.reg"     2>$null
Get-ItemProperty 'HKLM:\SOFTWARE\Classes\SiemensHMI.TIA.HmiSRT.V16' | Select-Object -ExpandProperty '(default)'

Registry Layout Created by the Fix

Importing the two .reg files populates the following logical structure. The exact GUIDs vary by TIA Portal version but the layout is stable from V14 through V18.

On a 64-bit Windows installation the 32-bit in-proc server is registered under HKLM\SOFTWARE\WOW6432Node\Classes; regedit shows both views through the standard WOW6432Node redirector.

Verification

After completing the fix, validate success using three independent checks before resuming development:

1. Registry presence. reg query "HKLM\SOFTWARE\Classes\SiemensHMI.TIA.HmiSRT.Vxx" returns a default value and a CLSID subkey.
2. COM instantiation. From an elevated PowerShell prompt run:

   $type = [Type]::GetTypeFromProgID('SiemensHMI.TIA.HmiSRT.V16','localhost')
   if ($type -eq $null) { Write-Error 'ProgID not resolvable' } else { Write-Host 'OK:' $type.FullName }

   A non-null FullName confirms the class is registered end-to-end.
3. Functional simulation. In TIA Portal, open any HMI device, click the Start simulation toolbar button, and confirm the simulator window appears within 10 seconds with no error dialog. Press F5 to force-refresh the connection to the simulated PLC and verify tag exchange.

Troubleshooting Matrix

Advanced Diagnostics

When the standard fix does not work, capture deeper evidence before contacting Siemens Industry Online Support:

• Process Monitor trace. Filter for regsvr32.exe, HmiSRT.exe, and regedit.exe while reproducing the error. The trace will show exactly which registry path is queried and the NAME NOT FOUND result.
• COM activation log. Enable HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Ole\EnableLogging = 1 (REG_DWORD) and restart TIA. The log at %TEMP%\OLE.LOG contains every CoCreateInstance attempt and the resulting HRESULT.
• SxS (side-by-side) manifest check. If the message changes to 0x800736B1 after the fix, the Win32 SmartSimulator manifest is missing. Reinstall the WinCC Runtime Advanced feature set.
• Procmon boot log. Capture from cold boot to first simulation attempt; the resulting PML can be filtered on RegOpenKey against SiemensHMI.TIA.HmiSRT to identify who is removing the keys.

Preventive Measures

• Install as administrator from a clean boot, with all AV products disabled or scoped to a temporary exclusion list for C:\Program Files\Siemens.
• Document the two .reg files in your image-build checklist. After each TIA upgrade, re-run HmiSRTRegister_reg and re-import the resulting files to bake the keys into the gold image.
• Avoid uninstalling a higher TIA version first. Downgrades from V18 to V16 frequently leave orphan V18 CLSIDs that mask the V16 ones. Uninstall all TIA versions, then install from oldest to newest.
• For terminal servers / Citrix VDI, publish the registry import as a logon script so every user session receives the keys, regardless of image persistence.
• Back up the working registry after a known-good install:

  reg export HKLM\SOFTWARE\Classes\SiemensHMI.TIA.HmiSRT.V16  C:\backup\HmiSRT_V16.reg /y
  reg export HKLM\SOFTWARE\WOW6432Node\Siemens\Automation  C:\backup\TIA_V16_path.reg /y

  Restore with reg import if a future TIA update drops the keys again.