Resolving OS Client Download Failure - Could Not Be Copied or Copied Partially in SIMATIC PCS 7

An OS Client download failure reporting 'Could not be copied or could only be copied partially' (Source: D:...\wincproj\ Target: \OSC02\Project...) occurs when the Engineering Station (ES) cannot write the WinCC client project across the Terminal Bus. The primary causes are active file locks from a running WinCC runtime or CCProjectMgr.exe process on the client workstation, missing Windows folder sharing permissions on the target directory, or a NetBIOS computer name mismatch in SIMATIC Shell. To resolve this, close WinCC on the OS Client, share the destination folder with full control for the 'SIMATIC HMI' user group, and re-execute the download from SIMATIC Manager.

OS Client Download Architecture and Terminal Bus Sharing

In SIMATIC PCS 7 distributed architectures, OS Client projects are configured and maintained on the central Engineering Station (ES). When changes are made, the ES compiles the client project and transfers it across the Terminal Bus to the physical OS Client workstation via Windows SMB file sharing.

The transfer process requires:
1. Target Directory Share: The OS Client destination directory (e.g. C:\Project\ or D:\Project\) must be shared on the network with full read/write permissions.
2. User Group Membership: The logged-on Windows user on the ES must belong to the local Windows user group SIMATIC HMI on both the ES and the target OS Client workstation.
3. Unlocked SQL Project Database: The target client WinCC project database (*.mcp, *.mdf, *.ldf) must not be locked by active processes.

Root Causes of Copy and Download Failures

The error could not be copied or could only be copied partially is triggered by specific constraints:
* WinCC Runtime or Background Services Active: If WinCC Runtime is running on the OS Client, or if WinCC Explorer was closed but background processes (such as CCProjectMgr.exe, CCClient.exe, or CCApp.exe) remained hung in Windows Task Manager, project files remain locked.
* Incorrect Share Permissions: If the target folder is shared as read-only, or if NTFS security permissions omit the SIMATIC HMI group, file transfer fails midway.
* Mismatched Computer Name: If the computer name defined in the WinCC project properties on the ES does not match the actual Windows NetBIOS name of workstation OSC02, SQL Server rejects project attachment.
* Terminal Bus Subnet Isolation: If the ES and OS Client communicate across different subnets without a functioning SIMATIC Shell multicast proxy, the UNC path \\OSC02\Project\ fails during large binary file transfer.

Remediation Procedure - Unlocking and Re-Sharing the Client Path

Follow this standardized workflow to restore OS Client target downloading:

[Phase 1: Prepare the Target OS Client (OSC02)]
   │  • Deactivate WinCC Runtime on OSC02
   │  • Close WinCC Explorer completely
   │  • Open Windows Task Manager -> Details tab:
   │      - End tasks: CCProjectMgr.exe, CCHmiScriptHost.exe, gcs.exe (if lingering)
   │  • In Windows Explorer: Right-click target folder (e.g. C:\Project\) -> Properties
   │      - Sharing Tab -> Advanced Sharing -> Share this folder -> Permissions:
   │          Add "SIMATIC HMI" -> Grant "Full Control"
   │      - Security Tab (NTFS):
   │          Add "SIMATIC HMI" -> Grant "Full Control"
   │
[Phase 2: Verify SIMATIC Shell and Network Visibility]
   │  • On OSC02: Open Windows Explorer -> Network -> SIMATIC Shell -> Settings
   │  • Confirm Terminal Bus network adapter is selected
   │  • From ES command prompt: Ping OSC02 and test UNC share:
   │      net view \OSC02
   │
[Phase 3: Execute Target Download from ES]
   │  • On ES: In SIMATIC Manager, select OS Client object
   │  • Right-click -> PLC -> Download -> Select "Entire project"
   │  • Download transfers the .mcp and client database cleanly!

Download Diagnostic Checklist and Parameter Matrix

Verify the following network and configuration parameters prior to downloading:

Layer / ParameterRequired OS Client SettingEngineering Validation MethodWindows Folder ShareFull Control for SIMATIC HMICheck Advanced Sharing permissions on \\OSC02\Project.NTFS File PermissionsFull Control for SIMATIC HMI and UsersCheck Security tab on local folder properties.WinCC Process StateCompletely closed; CCProjectMgr.exe killedInspect Windows Task Manager process list on OS Client.SIMATIC Shell AdapterTerminal Bus NIC selectedRight-click SIMATIC Shell -> Settings -> Network Adapter.Computer Name SyncExact match in WinCC Explorer and WindowsVerify NetBIOS computer name matches OS Client object in ES.Disk Space AvailabilityMinimum 10 GB free space on target partitionCheck Windows Explorer drive properties on OS Client.

Verification

To confirm that the OS Client download succeeded:
1. In SIMATIC Manager on the ES, verify that the download progress bar completes to 100% without error dialogs.
2. Log onto the physical OS Client workstation OSC02; navigate to the destination folder and verify that the .mcp project file and associated subfolders exist.
3. Open WinCC Explorer on OSC02; verify that the project opens immediately without database attachment errors.
4. Activate WinCC Runtime on OSC02; confirm that graphics pictures load and process tags display live values from the redundant OS Servers.

Limitations and Operational Precautions

Never execute an OS download while network cables are unstable or during high plant bus traffic. If downloading an OS Server or Client that is actively in runtime, use 'Changes only' mode where supported, or coordinate with operations before stopping the station. Never grant universal Everyone: Full Control on production SCADA shares without consulting site cybersecurity policies; restrict access strictly to the SIMATIC HMI user group.

Engineer FAQ

Why did the download fail after copying 90% of the files?

Large archive or database files (such as .mdf or .ldf) are transferred last. If SQL Server on the client workstation has not released the database lock, the transfer aborts at the final step.

Can I copy the OS Client project manually using a USB drive?

While manual copying is technically possible, you must run the Siemens Project Duplicator or reset project settings to adapt computer names and register the local SQL database.

What does 'Target path invalid' indicate during OS download?

It indicates that the UNC path configured in the OS Object properties (e.g. \\OSC02\Project\) cannot be resolved over the network due to DNS, WINS, or missing folder shares.

Why must the user belong to the 'SIMATIC HMI' group?

Siemens PCS 7 enforces role-based DCOM and file access permissions. Only accounts in the SIMATIC HMI group have rights to access SQL databases and WinCC communication pipes.