Resolving SIMOSIM Missing Virtual Ethernet Adapter in Scout TIA

Problem Details

SIMOSIM, the SIMOTION simulation add-in for SIMOTION SCOUT TIA, depends on a Microsoft KMDF-based virtual Ethernet adapter (commonly shown in Windows as SIMOSIM Virtual Ethernet Adapter or a TAP/NDIS device named during the SCOUT installation). The adapter is the network endpoint that allows the SCOUT engineering station, the TIA Portal project, and the running SIMOSIM instance to exchange PROFINET, TCP/IP, and RPC traffic.

When the adapter disappears from the Windows network adapter list, the simulation can still be opened in SCOUT, but the device is unreachable: online connection requests time out, the Go online dialog cannot find a target, the device IP appears offline, and the Load project to target system function returns a routing error. Reinstalling SCOUT or SIMOSIM does not always bring the adapter back, because the failure usually occurs in the driver registration step, not in the application payload.

Affected Versions and Environment

The symptom is not version-specific. It is observed after Windows feature updates, large cumulative updates, antivirus scans that quarantine unsigned driver files, group policy changes, or workstation domain changes (which alter the access token used during installation).

Root Cause Analysis

SIMOSIM ships a third-party virtual NIC driver that registers itself as a kernel-mode device under \\.\\<DeviceName> and as a Windows network adapter in Device Manager > Network Adapters. If the driver store entry, the device class GUID, or the service entry is missing or marked as Type 1 (Boot)/Type 3 (Demand) incorrectly, the adapter will not enumerate. The three root causes that recur in field reports are summarized below.

Diagnostic Procedure

1. Confirm the adapter is missing. Open Device Manager → View → Show hidden devices → Network adapters. If SIMOSIM Virtual Ethernet Adapter is not listed, the driver is not enumerated, and SCOUT will not find the target.
2. Inspect the install log. Navigate to %TEMP% or the SCOUT install directory and open install_simosim_driver_log.txt (and install_simosim.log if present). Look for the lines:

   Installing driver: SIMOSIM Virtual Ethernet Adapter
   DiInstallDriver returned: 0x00000000  <-- success
   DiInstallDriver returned: 0x80070005  <-- access denied
   DiInstallDriver returned: 0x800F0247  <-- INF signature missing / driver blocked by policy
   

3. Check the driver store. Run pnputil /enum-drivers in an elevated command prompt. Locate the published name that contains Simosim or the OEM string from SCOUT. If absent, the INF was not registered. If present with Flags: 0x0, the driver is staged but not active.
4. Check the service entry. Run sc qc <ServiceName> for the SIMOSIM NDIS entry. Confirm START_TYPE is 0x0 (Boot), 0x1 (System), or 0x3 (Demand) with START_TYPE_AUTO for the SCOUT runtime.
5. Verify subnet isolation. Run ipconfig /all on the SIMOSIM virtual adapter once it reappears. Confirm the IP belongs to a /24 that does not overlap with any production SIMOTION subnet, per the SIMOSIM subnet isolation note (SIOS ID 109986921).

Install Log Analysis

The file install_simosim_driver_log.txt is the single most informative artifact for this fault. Common error tokens and their meaning are listed in the table below.

Driver Reinstallation Procedure

Use the following ordered procedure to recover the SIMOSIM virtual Ethernet adapter.

1. Stop SCOUT and the TIA Portal gateway. Close the TIA Portal, SCOUT TIA, and the S7DOS Helper Service from services.msc. This releases the device handle that SCOUT keeps open while the simulation is running.
2. Reboot the workstation. A full power cycle, not a sleep/wake cycle. Sleep states preserve stale driver handles; only a cold boot clears the kernel PnP state.
3. Wait for Windows Update to settle. If a feature or cumulative update was pending, allow it to complete and reboot a second time before reinstalling. A pending update re-stages the driver store and is the most common reason a re-install of SCOUT alone fails to register the adapter.
4. Run setup from an elevated token on the corporate network. Right-click Setup.exe of the SIMOSIM install media and choose Run as administrator. The corporate domain token grants SeLoadDriverPrivilege required by DiInstallDriver; local-only accounts on home networks typically do not have it.
5. Watch for the install log. Confirm install_simosim_driver_log.txt reports DiInstallDevice succeeded. Do not dismiss the install window until the line is present.
6. Reboot again. The driver must load at boot to bind the device class GUID. A second reboot is required even if the install reports success.
7. Verify in Device Manager. Open Device Manager → Network Adapters. The SIMOSIM Virtual Ethernet Adapter should appear without the ! (yellow bang) icon.

Subnet and Network Configuration

Per the official Siemens support article 109986921 (Using SIMOSIM - SIMOTION SCOUT TIA), three conditions must hold for SIMOSIM to communicate with SCOUT and TIA Portal:

1. The SIMOTION device (real or simulated) and the SIMOSIM virtual adapter must be in the same IP subnet.
2. No active online connection to a real SIMOTION device may exist while SIMOSIM is in use. A live PROFINET session to a physical controller is multiplexed over the same SCOUT routing table; running both at once makes the SIMOSIM endpoint unreachable.
3. The SIMOSIM instance must not be bound to a subnet that contains the engineering station's primary physical adapter, otherwise Windows ARP resolution favors the physical NIC and the SIMOSIM adapter enters a fallback state.

Verification

After recovery, run the following sequence to confirm the adapter is operational:

1. Adapter visibility. ipconfig /all lists the SIMOSIM adapter with the assigned IP and shows Media State: enabled.
2. Loopback test. ping 192.168.214.1 -S 192.168.214.2 (sourcing from the SIMOSIM adapter) replies with 0% loss. If the ping resolves through the physical NIC, the routing table needs a route add entry that pins the SIMOSIM subnet to the virtual adapter index.
3. SCOUT Go online. In the project tree, right-click the SIMOTION device and choose Target system → Go online. The status line reports Online (SIMOSIM), not Cannot reach target.
4. Project load test. Download the project to the SIMOSIM instance with Load to target system. The transfer completes within a few seconds and the device shows a green check in the project tree.
5. PROFINET trace. Start a trace in SCOUT and confirm PROFINET frames are seen on the SIMOSIM interface using PROFINET Diagnosis → Ethernet Statistics.

Troubleshooting Matrix

Frequently Asked Questions