Resolving TIA Portal V20 WinCC Install Errors After V17 Upgrade

1. Overview

Siemens TIA Portal does not behave like a traditional in-place software update. When moving from TIA Portal V17 to TIA Portal V20, the supported path is a clean uninstall of the prior major release followed by a fresh install of the new release, not an automated upgrade. Attempting to chain a V17 WinCC install into a V20 install sequence is the most common cause of the install failure mode described in field reports:

• The TIA Portal V20 base install completes, but the WinCC component (Comfort, Professional, or Unified) refuses to install.
• The TIA Administration Tool reports a version mismatch (e.g., V1 still present while V3 is being requested).
• The installer rolls back partway through, leaving the system in a hybrid state that blocks subsequent install attempts until cleaned.

The TIA Administration Tool is a shared service component common to all installed TIA Portal versions. When the major version of the tool increments (as it did when moving from V17 to V20), older versions cannot be migrated upward; they must be removed. This article documents a deterministic, repeatable field procedure for resolving V20 install failures on a workstation that previously ran V17 with WinCC Comfort and is now being targeted for WinCC Unified Basic.

2. Affected Versions and Symptoms

Recognized symptom patterns reported in the field:

1. Error message indicating the TIA Administration Tool is in an inconsistent state.
2. The WinCC setup launches, then immediately aborts with no useful error code.
3. A second install attempt fails earlier in the process because partial files from the failed install are present in %ProgramData%\Siemens\Automation.
4. Windows Installer (MSI) reports a return code in the 1603 to 1638 range when launching the TIA Administration Tool removal.

3. Root Cause Analysis

The TIA Administration Tool acts as the gatekeeper for all TIA Portal-related install, repair, modify, and remove operations. Its major version is tied to the TIA Portal major release:

When a V20 installer detects an active V17 install, the installer's pre-flight check attempts to call the TIA Administration Tool to enumerate installed products. If the tool's internal version is older than what the V20 installer expects for cross-version inventory, the operation is aborted to prevent the tool from corrupting its database. The user sees the equivalent of "TIA Admin Tool got upset." The same logic applies in reverse: trying to repair or remove V17 components while V20 is partially installed produces a symmetric failure.

A secondary root cause is component interlock between WinCC Pro and WinCC Unified installers. The V20 media contains two distinct installer bundles:

• TIA Portal V20 + WinCC Professional V20 (single DVD / OSD package)
• TIA Portal V20 + WinCC Unified V20 (separate, Unified-specific bundle)

These bundles are not interchangeable. If V20 base was installed from the Pro bundle but WinCC Unified Basic is also required, the Unified bundle must be installed additionally, not as a replacement. Conversely, if the Unified bundle was used to install the base, attempting to add WinCC Pro will be blocked.

4. Pre-Installation Cleanup Procedure

Before any V20 install is attempted on a workstation that previously held V17, perform the following cleanup in order. Skipping steps is the most common cause of recurring failures on the second install attempt.

4.1 Capture License State

1. Open the TIA Administration Tool (Start → Siemens Automation → TIA Administration Tool).
2. Navigate to the License management view and export a list of all license keys currently bound to the workstation.
3. Save the export and the license certificates to a network share. V20 licenses are not the same certificate files as V17; the existing V17 certificates cannot be migrated.

4.2 Uninstall All TIA Portal Components

1. Open Control Panel → Programs and Features (or Settings → Apps → Installed apps on Windows 10/11).
2. Sort by publisher and locate every entry published by Siemens AG.
3. Uninstall in this order:
     a. WinCC Runtime / Comfort / Advanced / Professional (whichever are present)
     b. SIMATIC HMI components
     c. STEP 7 / TIA Portal main entry
     d. SIMATIC PLCSIM (if installed)
     e. TIA Administration Tool (last, so it remains available to remove the other entries)

4.3 Reboot and Verify

1. Reboot the workstation. The Windows Installer service must reset after the chained removals.
2. Re-open Programs and Features and confirm no Siemens entries remain.
3. Verify the following directories are empty (do not delete them — confirm only):
   • C:\Program Files\Siemens\Automation
   • C:\ProgramData\Siemens\Automation
   • %LOCALAPPDATA%\Siemens\Automation

4.4 Clear Stalled Installer State

If a previous install attempt was aborted, the Windows Installer may have pending operations locked. Clear them:

cmd /c msiexec /unregister
cmd /c msiexec /regserver

Then rename (do not delete) the installer patch cache so it rebuilds on next install:

ren "%WINDIR%\Installer\$PatchCache$" "$PatchCache$_old_%DATE:~10,4%%DATE:~4,2%%DATE:~7,2%$"

4.5 Manual MSI Removal (Recovery Path Only)

If the TIA Administration Tool was removed prematurely and the standard uninstall path is no longer reachable, recover with:

1. Open regedit as administrator.
2. Export HKLM\SOFTWARE\Siemens\Automation for backup.
3. Locate the product GUIDs in HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall whose Publisher is "Siemens AG".
4. For each GUID, run: msiexec /x {GUID} /qb REBOOT=REALLYSUPPRESS

4.6 Disable Antivirus and Windows Defender Real-Time Scan

Both the TIA Portal installer and the SIMATIC HMI installer unpack large amounts of compressed payload into the Windows Installer cache. Real-time scanning during this phase causes path-length errors and "out of disk space" false-positives. Exclude the following paths temporarily for the install window only:

• C:\Program Files\Siemens\
• C:\ProgramData\Siemens\
• %WINDIR%\Installer\

5. Fresh V20 Installation Procedure

5.1 Confirm Prerequisites

5.2 Download the Correct V20 Bundle

1. Log in to Siemens Industry Online Support with your SID/SIS subscription.
2. Navigate to My Software & Downloads.
3. For the V20 base + WinCC Professional target, download the TIA Portal V20 + WinCC Professional V20 bundle (single OSD delivery).
4. For the V20 base + WinCC Unified target (as in the source scenario), download the TIA Portal V20 + WinCC Unified V20 bundle — a separate package.
5. For projects that must use both Pro and Unified, download both bundles and install sequentially, with a reboot between them.

5.3 Install Order

1. Mount the ISO or extract the OSD download to a local folder on the workstation (not a network share — the installer is UNC-sensitive).
2. Right-click Start.exe → Run as administrator.
3. Select Install TIA Portal. Allow the TIA Administration Tool V3 to deploy first.
4. When the component selection screen appears, enable only the components required: STEP 7 Professional, WinCC Unified (Basic/Comfort/Advanced per license), PLCSIM if used.
5. Complete the install and reboot when prompted. Do not skip the reboot — the HMI runtime services are bound to the new TIA Administration Tool registration and require a clean Windows service start.

5.4 Validate the TIA Administration Tool

1. Open the TIA Administration Tool.
2. Confirm the version banner shows V3.x.
3. Confirm the workstation is listed under Computers and the OS agent status is green.
4. Run Check & repair against the local computer. This must complete with zero errors before any project work begins.

6. WinCC Pro vs. WinCC Unified — Choosing the Right Bundle

For the source scenario (V17 Comfort → Unified Basic), the user wants to move from a Comfort-style project to the Unified paradigm. The correct bundle is the TIA Portal V20 + WinCC Unified V20 package, and the legacy V17 Comfort project must be opened in V20 Unified's Migration Tool, not directly. Direct opening is unsupported and will produce a build error that is sometimes misreported as a runtime error.

7. Virtual Machine Strategy for Multi-Version Coexistence

Field reports indicate that maintaining two TIA Portal major versions side-by-side on one workstation is officially supported only within a narrow window (consecutive major versions during project handover). Once a release goes out of service, Siemens does not guarantee side-by-side operation. The deterministic way to keep a V17 environment alive while running V20 production is virtualization.

7.1 Recommended Hypervisor

7.2 VM Build Procedure for V17 Retention

1. Allocate a dedicated VHDX/VMDK of at least 200 GB (thin-provisioned) for the V17 VM.
2. Install Windows 10 IoT LTSC 2019 — the OS that V17 was validated against.
3. Snapshot the clean OS as Base.
4. Mount the V17 media (DVD or OSD ISO), run Start.exe as administrator, install STEP 7 V17 and WinCC Comfort/Advanced V17.
5. Activate licenses inside the VM (the VM's UUID/MAC is the license target, not the host's).
6. Apply all V17 service packs and updates within the VM only.
7. Snapshot as V17 Production.

7.3 Workstation Architecture

Use the following split:

• Host (bare metal): TIA Portal V20 + WinCC Unified V20 (active project work).
• VM (offline / occasional): TIA Portal V17 + WinCC Comfort V17 (legacy project maintenance, archive retrieval, customer support).

8. Verification and Commissioning

After install, run this verification sequence. All steps must pass before opening a project.

8.1 Service and Process Check

sc query "Siemens TIA Admin Agent"
sc query "SIMATIC HMI"
sc query "WinCC Unified Server"

All three should report STATE: 4 RUNNING. If any are stopped, check the Windows Event Viewer under Applications and Services Log → Siemens for the start failure reason.

8.2 Project Open and Compile

1. Launch TIA Portal V20.
2. Open a known-good test project that matches the installed WinCC edition.
3. Compile the HMI: Project tree → HMI_1 → Compile → Software (rebuild all).
4. Confirm zero errors and zero warnings in the Inspector window.

8.3 Runtime Simulation

1. Start the HMI runtime: Project tree → HMI_1 → Start runtime.
2. Verify the project launches in the simulator window within 30 seconds.
3. Toggle a tag and confirm the HMI updates — confirms OPC UA / S7 channel binding.

8.4 License Binding Verification

1. Open the TIA Administration Tool.
2. Confirm all expected license keys show valid (green check).
3. Confirm license server (if using network licensing) shows the workstation as a client.

9. Troubleshooting Matrix

10. Field-Proven Best Practices

1. Never mix bundles on the same workstation. Use the Unified bundle from the start if Unified is the target.
2. Always uninstall TIA Administration Tool last. It is the lynchpin for every other component's removal.
3. One major version per workstation OS install. Use VMs for parallel major versions.
4. Snapshot VMs after every successful service pack. This creates a clean rollback path when an install fails.
5. Document the bundle used. Record the OSD delivery note number in the project README so future engineers know which installer set built the project.
6. Use SSD storage only. TIA Portal V20 HMI compile times on HDD exceed reasonable interactive thresholds and can trigger installer timeouts during repair operations.
7. Keep the Windows Installer cache healthy. Disk pressure on %WINDIR%\Installer causes silent rollbacks.

11. FAQ