Resolving WinCC Professional V11 Computer Name Compile Error

Problem Description

A compile error is reported in WinCC Professional V11 (TIA Portal) when configuring a client/server project under WinCC > Server for Runtime Professional. The compiler flags the Computer name field of the WinCC server or client device as invalid, aborting the build and preventing the runtime project from being generated. The error is reproducible across all TIA Portal V11 and V11 SP1 service packs and is independent of project size, HMI tag count, or screen complexity.

Typical symptoms observed in the field:

• Compile log shows Error: The computer name is not valid or Error in parameter "ComputerName" of device <HMI_RT>.
• The error appears immediately after pressing Compile > Software (rebuild all) with the server or client HMI device selected.
• The Windows hostname of the engineering PC and the value entered in the WinCC device configuration Computer name field do not match exactly.
• A trailing dot, hyphen, or special character appears at the end of the hostname when viewed from System Properties or from cmd > hostname.

WinCC Professional V11 Client/Server Architecture Overview

WinCC Runtime Professional is a PC-based SCADA runtime that communicates with the TIA Portal engineering station over the same project used to program SIMATIC S7-1500/300/400 controllers. In a multi-station installation, one PC acts as the WinCC server and one or more PCs act as WinCC clients. The server holds the active process image, archives, alarms, and reports; the clients render the screens served by the server.

For the client/server split to compile correctly, the following prerequisites must be satisfied (per the official Siemens TIA Portal V20 documentation for Clients and servers (RT Professional) — the architectural rules apply back to V11):

1. A valid WinCC RT Professional license must be installed on the server PC.
2. Each WinCC client requires a WinCC RT Professional client license.
3. The Computer name of every HMI device in the project must match the Windows hostname of the PC that will run that role.
4. The server and clients must be reachable on the same subnet; multicast / UDP discovery must be permitted on the network.
5. The SQL Server instance backing WinCC must be configured to allow the WinCC service accounts to start, stop, and create databases.

Failure of any of the above produces a compile-time error before the runtime is even generated. Of these, the hostname mismatch is by far the most common in fresh installations.

Root Cause: Computer Name Restrictions

WinCC Professional V11 performs a compile-time check on every HMI device's Computer name property. The check enforces the same character and length rules as a NetBIOS / DNS hostname, but with the additional Siemens restriction that no trailing dot or hyphen is allowed. This is the root cause behind the original report, where the Windows hostname was displayed as winimage. (with a trailing period) — the period is the FQDN delimiter that DNS resolvers append automatically, but the WinCC parser interprets it as an invalid character and aborts the build.

There are four classes of hostname that will trigger the compile error:

The error is deterministic: the same invalid name will always fail to compile, regardless of user permissions, project size, or TIA Portal hotfix level.

Windows Hostname Rules and the WinCC Subset

Windows allows hostnames that violate the strict DNS letter rules if the NetBIOS compatibility layer is enabled. WinCC Professional V11 does not honor that compatibility — it applies the stricter Siemens subset. Use the following table as the authoritative reference when choosing a name:

Step-by-Step Resolution

Follow this sequence to clear the compile error and deploy the WinCC server/client pair successfully.

Step 1 — Capture the current Windows hostname

1. Open an elevated Command Prompt.
2. Run hostname and echo %COMPUTERNAME%. Both must return the same string.
3. Run ipconfig /all and note the Primary DNS Suffix — this is the value Windows appends when it shows the hostname with a trailing dot.
4. Open System > About > Rename this PC (advanced) and compare the value to what is stored in the registry under HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Hostname.

Step 2 — Rename the Windows computer

1. Open Start > Control Panel > System and Security > System > Rename this PC.
2. Enter a name that satisfies the WinCC subset: 1–15 characters, alphanumeric plus hyphen, alphanumeric first and last, no trailing punctuation.
3. Click Next and restart the PC. A reboot is mandatory — WinCC services cannot reload the hostname at runtime.
4. After reboot, run hostname again to confirm the new value. There should be no trailing period.

Step 3 — Update the TIA Portal project

1. Open the project in TIA Portal V11 / V11 SP1.
2. Select the WinCC server device in the project tree.
3. Open Properties > General > Computer name and replace the value with the new Windows hostname, in the same letter case (uppercase is recommended for consistency).
4. Repeat for every WinCC client device that participates in the project.
5. Right-click the project and choose Compile > Software (rebuild all).

Step 4 — Verify the project compiles

1. The compile log under Info > Compile should now end with Compile finished without errors.
2. Open the Project tree > WinCC RT Professional > Server data and confirm the entry under Computer list matches the Windows hostname character-for-character.
3. Proceed to Download to target device.

TIA Portal V11 SP1 Specific Configuration

The V11 SP1 readme (Siemens Support entry 51784423 — WinCC Professional V11 SP1 readme) lists several post-installation steps that interact with the hostname. The SQL Server instance used by WinCC must be reachable under the new computer name, otherwise the runtime will start in a degraded state even though the compile succeeded.

1. Open SQL Server Configuration Manager on the WinCC server.
2. Under SQL Server Services, confirm the WINCC instance is running. The instance name is normally WINCC and binds to the local machine identity.
3. Under SQL Server Network Configuration > Protocols for WINCC, enable TCP/IP and disable Named Pipes if the clients will reach the server over IPv4.
4. Restart the SQL Server (WINCC) service so the new hostname is registered in the SQL metadata.
5. Open Start > Programs > Microsoft SQL Server > SQL Server Management Studio, connect to localhost\WINCC with Windows authentication, and verify the master database lists the new hostname in sys.servers (column name).

License Requirements

Even when the compile error is fixed, the project will not start at runtime without the correct licensing. The license model is identical from V11 through V20:

Verification Checklist

Before declaring the fix complete, walk through this matrix and tick every row:

Troubleshooting Matrix

Related Configuration Items Worth Checking

Even after the computer-name issue is resolved, three supporting settings are responsible for the majority of follow-on errors reported on the Siemens support portal:

1. Windows Firewall — open UDP 5001, UDP 5002, and TCP 5000 inbound on the server. These ports are used for client/server discovery and the WinCC channel RPC traffic.
2. DCOM and RPC — WinCC uses DCOM for tag and alarm exchange. The COM Security settings under dcomcnfg must allow Everyone access if the PC is in a workgroup; in a domain, the WinCC service account must have launch and activation rights.
3. Time synchronization — alarms and archive entries are timestamped. A clock skew larger than five seconds between server and client causes Invalid time stamp warnings and is a common source of confusion on commissioning day. Configure an NTP source on both PCs.

What to Do If the Error Persists

If the compile log continues to report Computer name is not valid after Steps 1–4 above, the issue is almost always in the project cache rather than the OS hostname:

1. Close TIA Portal and stop the Siemens TIA Portal V11 service.
2. Navigate to the project folder and delete the System\<CPU name>\IM\<device> subfolder, then delete the .srf and _logs folders.
3. Reopen the project, perform a full Compile > Software (rebuild all), and verify the log.
4. If the error still appears, open a support request on the Siemens Industry Online Support portal and attach the full compile log plus a screenshot of cmd > hostname and the device property sheet.