Problem Details
When compiling or downloading a TIA Portal V17 project that targets a SIMATIC WinCC Unified PC runtime, the engineering station aborts with a dialog stating that the required software is not available or installed. The error typically references WinCC Unified PC V1 as the missing component, even when the user has previously installed WinCC Unified components via the TIA Portal setup. The message is misleading: the runtime is rarely missing, but TIA Portal cannot locate a compatible Engineering System (ES) instance bound to the same software generation and update level.
Common observable symptoms include:
- Compile of the HMI device fails with: "The software WinCC Unified PC V1 is not installed."
- Download to the Unified PC target aborts before any PLC/HMI handshake is attempted.
- Reinstalling the WinCC Unified package, switching to V4, or reinstalling the full TIA Portal suite does not clear the error.
- The Installed software tab in the TIA Portal setup reports that WinCC components are present, but only the Simulation and RT options are checked — the ES option for Unified is unchecked.
V1 in the error does not refer to a WinCC version number. It is the internal step-7/TIA step name of the WinCC Unified PC configuration plug-in. The actual installed version of the package (V16, V17, V18, V19, V20) is read from the registry and the installed product list. The error therefore always reads WinCC Unified PC V1 regardless of which major release is in use.
Root Cause Analysis
There are three independent root causes that produce the same dialog. They must be ruled out in this order because each successive cause requires a more invasive fix.
Cause 1 — Update-Level Mismatch (most common)
TIA Portal couples the project metadata to a software generation + update level signature. If the project was last saved with TIA Portal V17.0 + WinCC Unified V17.0 Update 1, the loader expects the same exact build on the engineering station. A machine that has TIA Portal V17.0 base and Unified PC V17.0 base (no Update 1, or Update 2/3/4 installed) returns the "V1 unavailable" error even though some Unified component is installed.
According to the official Siemens support entry 109784441 — WinCC V17 ES update downloads, every Unified PC hotfix is delivered as a discrete HWUpdate package. Engineering stations and target PCs must be patched with the matching .upd file, or the loader refuses to instantiate the plug-in.
Cause 2 — Missing "Unified ES" Selection During Setup
The TIA Portal setup wizard distinguishes between three Unified product lines:
| Setup Option | Role | Why It Must Be Selected |
|---|---|---|
| WinCC Unified ES | Engineering plug-ins (screens, tags, scripts) | Provides the V1 plug-in identity the project looks for at compile time |
| WinCC Unified RT | Runtime on the target PC | Allows project execution on the PC; not sufficient for offline compile |
| WinCC Unified Simulation | Local RT simulator for testing | Provides the local-only simulator; cannot compile production projects |
If only RT and Simulation were selected during the original TIA Portal setup, the engineering station has no V1 plug-in registered. The setup must be re-launched with Modify and the WinCC Unified ES option checked.
Cause 3 — Stray Unified PC ≤ V18 Installations Blocking the Plug-in
Siemens Knowledge Base article 109822246 — Error with parallel installation WinCC Unified & Professional documents a known condition where leftover binaries from an older WinCC Unified PC Engineering or WinCC Unified PC RT installation (≤ V18) prevent the newer plug-in from registering. The Microsoft Installer rollback on a partially failed upgrade leaves orphaned registry entries under HKLM\SOFTWARE\Siemens\Automation\WinCC Unified and HKLM\SOFTWARE\WOW6432Node\Siemens\Automation\WinCC Unified. These entries are not removed by the standard TIA Portal setup's Repair action.
Solution Procedure
Follow the steps below in order. Do not skip the registry/folder inspection in step 3 — the parallel-installation case is invisible to the TIA Portal setup GUI.
Prerequisites
- Local administrator rights on the engineering PC.
- Access to the Siemens Industry Online Support download portal with a valid Siemens customer account.
- The TIA Portal installation media (DVD image or downloaded
.exe) matching the project's software generation (V17 in the canonical case). - A licensed or trial dongle (CSA or local license server) for WinCC Unified V17 ES.
Step-by-Step
-
Capture the project signature. Open the project in TIA Portal V17, then read Project > Properties > TIA Portal version and Project > HMI device > Properties > Software version. Record the exact string, e.g.
V17.0 Update 1. This is the target update level for the engineering station. -
Install the matching update. Download the update package from entry 109784441 and run the
.updfile. The installer reports success only when the base installation and the update apply to the same major version. If the installer rejects the update, the base TIA Portal installation is a different major version and must be re-installed first. -
Remove any parallel WinCC Unified PC ≤ V18 install. Open Control Panel > Programs and Features and uninstall, in this order:
- SIMATIC WinCC Unified PC Engineering (any version ≤ V18)
- SIMATIC WinCC Unified PC RT (any version ≤ V18)
- SIMATIC WinCC Professional (only if you do not need the Comfort/Professional parallel stack)
C:\Program Files\Siemens\Automation\WinCC UnifiedC:\Program Files (x86)\Siemens\Automation\WinCC UnifiedC:\ProgramData\Siemens\Automation\WinCC Unified
-
Re-run TIA Portal setup and enable Unified ES. Launch
Start > Siemens Automation > TIA Portal V17 > Setup(or insert the install media and let autorun start the setup). Choose Modify, navigate to the WinCC product family, and tick the following checkboxes:-
☑ WinCC Unified ES(critical) -
☑ WinCC Unified Simulation(optional, for local RT testing) -
☐ WinCC Unified RT(skip on engineering PC unless it is also the runtime target)
C:for V17) and complete the install. -
- Reboot and re-license. Restart Windows. The unified V1 plug-in registers its COM classes only after a full reboot, not after a sign-out. Re-apply the WinCC Unified license from the Automation License Manager.
- Re-open the project and recompile. In TIA Portal, right-click the HMI device and choose Compile > Software (rebuild all). The compile should complete without the V1 dialog.
Edge Case — When "V1" Indicates a Genuine Version Mismatch
Beginning with TIA Portal V18, the error text was extended to include the resolved version. In V17, the message always reads V1, so engineers occasionally interpret it as a request for WinCC V1 (an obsolete WinCC flexible product). This is not the case — any TIA-Portal-V17-generation Unified PC package (V17, V17 Update 1 through V17 Update 5) is acceptable as long as it matches the project. The rule is:
All Unified ES + Unified RT + Unified Simulation components on both the engineering PC and the runtime PC must share the same major + minor + update level as the project file.
Verification
After completing the procedure, perform the following verification matrix.
| Check | Expected Result | Command / Location |
|---|---|---|
| Plug-in registered | File Siemens.Simatic.Hmi.WinCC.Unified.PC.ES.dll present |
C:\Program Files\Siemens\Automation\WinCC Unified\Bin |
| COM class available | Class ID resolves without error | Regedit: HKEY_CLASSES_ROOT\CLSID\{...WinCC.Unified.PC.ES...}
|
| TIA Portal recognizes ES | Right-click HMI device → "Compile" enabled (not greyed) | TIA Portal V17 |
| Compile completes | Output window shows "Compile completed successfully" | TIA Portal → Output → Compile |
| Download to PC RT | Transfer dialog closes, RT starts the project | TIA Portal → Online → Download to device |
Related Error Messages and Cross-References
The TIA Portal V17 / V18 loader raises a family of related messages that share a common diagnostic root. The official TIA Portal V20 help page Error messages during loading of projects (RT Unified) lists the most common ones.
| Symptom | Likely Cause | First Action |
|---|---|---|
| "WinCC Unified PC V1 is not installed" | ES plug-in missing or update mismatch | Re-run setup with Unified ES checked; apply matching .upd
|
| "Connection to the HMI device cannot be established" | Network/PG-PC interface misconfigured | Verify Ethernet link, Set PG/PC interface to the correct NIC, ping the Unified PC |
| "Error with parallel installation WinCC Unified & Professional" | Stray ≤ V18 binaries | See KB 109822246 |
| "WinCC Unified RT has a newer version than the ES" | RT was updated, ES was not | Apply same .upd to the engineering PC |
| "License for WinCC Unified PC not found" | License key mismatch or ALM service stopped | Restart ALM service; re-activate key |
Field-Proven Commissioning Notes
Several practices reduce the recurrence of this error in production environments.
-
Centralized update repository. Host the
.updfiles for every TIA Portal major version in a network share. After every Siemens update, push the same file to all engineering and runtime PCs. Update-level drift across a fleet is the leading cause of this dialog. -
Default install profile. Build a scripted (or
.issAnswer-File driven) TIA Portal setup that always selects Unified ES, Unified Simulation, and the SQL Server Express instance. A standardized install prevents the "ES unchecked" failure mode. - Pre-upgrade audit. Before installing a new TIA Portal major release (e.g. moving from V17 to V18 or V19), capture a screenshot of the V17 Installed Software tab. The list is the only authoritative record of which products are licensed and installed; it is lost when the old major version is uninstalled.
- Layered uninstall. When migrating, uninstall the old major first, restart, then install the new major. Skipping the restart between these steps is a documented trigger for the parallel-installation error.
- Watch the version number on the project file. Opening a V18 project in a V17 ES upgrades the project's metadata irreversibly. Confirm the engineering station is at the correct major version before opening the project.
Diagnostic Quick-Reference
| What You See | What To Do |
|---|---|
| Setup shows ES as installed, but compile still fails | Check the update level of the project (Project > Properties) against the installed ES update |
| Setup shows ES as not installed | Re-run setup in Modify mode and check the Unified ES box |
| Setup hangs or rolls back during ES install | Per KB 109822246, manually remove leftover ≤ V18 directories and retry |
| Project was migrated from V16 to V17, error appeared | Apply the V17 Update matching the engineering station; do not mix V16 RT and V17 ES |
| Multiple users on different PCs, error on one only | Compare the Installed Software list between the failing and working PC; restore the missing component |
Frequently Asked Questions
Does the "V1" in the error message mean I need WinCC version 1?
No. "V1" is the internal name of the Unified PC configuration plug-in and appears in every TIA Portal V17 error of this family. The actual installed version (V17, V17 Update 1-5, V18, V19, V20) is read separately from the project metadata; the dialog text is identical for all of them.
Can I keep WinCC Professional and WinCC Unified installed on the same PC?
Generally no for versions ≤ V18. Per Siemens KB 109822246, parallel installations of WinCC Professional and WinCC Unified PC ≤ V18 produce the "V1 unavailable" error. From V19 onward, Siemens has progressively moved to a single shared installer, but you should still verify the Installed Software tab before commissioning.
Will V2, V3, or V4 of WinCC Unified PC work if all components match?
No. The version after "V" (e.g. V2, V3, V4) is the WinCC flexible / WinCC classic version family and is unrelated to Unified. Unified is released only as V16, V17, V18, V19, V20, etc. The "V1" in the error refers to the Unified PC plug-in identifier, not a WinCC flexible version.
How do I check which update level of TIA Portal V17 is installed?
Open Help → Installed software in the TIA Portal menu, or check Control Panel → Programs and Features → SIMATIC TIA Portal V17. The "Update" column shows the current patch level (e.g. V17.0 Update 4). Compare this to the value under Project → Properties → TIA Portal version in the project.
Why does the Setup show ES as installed but the compile still fails?
Most often this is an update-level mismatch: the ES is at V17.0 base but the project requires V17.0 Update 1 (or higher). Download the matching .upd package from Siemens entry 109784441 and run it. The Update level, not the presence/absence of the component, is what the loader validates.