Best Practices for Archiving SIMATIC PCS 7 Multiprojects Without Database Corruption

In SIMATIC PCS 7, archiving a complete multiproject containing redundant WinCC OS servers and S7 controllers must be executed using the integrated SIMATIC Manager Archive function (File -> Archive) while all WinCC runtimes are deactivated and project editors are closed. Corrupted archives occur when Microsoft SQL Server database files (.mdf and .ldf) are locked by active runtime processes, when temporary runtime cache files are included, or when writing large archives across unstable network shares. Never use the WinCC Project Duplicator for multiproject backups, as it destroys plant hierarchy linkages. To ensure archive integrity, shut down OS runtime, delete temporary runtime databases, archive to a local hard drive, and verify with Retrieve.

SIMATIC PCS 7 Multiproject Archiving Architecture

A SIMATIC PCS 7 automation system is structured as a Multiproject (.s7p / .mcp) consisting of multiple decentralized sub-projects: one or more S7-400 AS projects containing hardware configurations and CFC/SFC charts, a Master Data Library, redundant WinCC OS Server projects, OS Client projects, and optional packages such as SIMATIC BATCH or Maintenance Station.

The SIMATIC Manager Archive utility (File -> Archive) is the official, engineered tool designed to package this entire distributed architecture into a single compressed archive file (.zip or .pkz). During archiving, the utility coordinates with the STEP 7 database engine to lock project folders, compress AS engineering databases, include WinCC graphics and tag dictionaries, and preserve the cross-project relationship table (Global.s7p).

PCS 7 natively utilizes PKZip (or an authorized version of WinZip configured within STEP 7 options) as its underlying compression engine. When executed correctly, the archive provides a 100% restorable snapshot of both controller software and HMI server configurations.

Root Causes of Corrupt Archives and Missing OS Databases

When engineers experience corrupted archives or find that an unarchived OS project fails to open in WinCC Explorer, technical investigation reveals four primary failure causes:

Archiving with Active WinCC Runtime or Open SQL Databases: WinCC OS projects store plant tags, alarms, and configurations inside Microsoft SQL Server database files (<ProjectName>.mdf and <ProjectName>.ldf). When WinCC Runtime is active, the SQL Server daemon (sqlservr.exe) holds exclusive write locks on these files. The compression engine cannot access the locked files, resulting in omitted databases, zero-byte transaction logs, or zip CRC errors.
Inclusion of Massive Historical Data Buffers: By default, long-term historical trend and alarm segments reside in the OS project's ArchiveManager directory. In operating plants, this folder can reach tens or hundreds of gigabytes. Attempting to compress this data within a standard multiproject archive causes memory exhaustion, exceeds 32-bit zip limits (4GB boundaries on older compression engines), and leads to archive corruption.
Network Storage Timeouts and SMB Disconnections: Archiving a multi-gigabyte project directly across a local area network to an SMB/CIFS network share is prone to packet drops and latency spikes. If the network connection drops for even a fraction of a second while the zip header is being finalized, the entire archive becomes unreadable.
Misuse of the WinCC Project Duplicator: The WinCC Project Duplicator tool is engineered exclusively for redundant OS server pairing (copying a project from Server A to Server B). Using it to back up a PCS 7 project breaks Plant Hierarchy pointers and removes OS-to-AS compilation cross-references.

Archiving Tool Comparison: SIMATIC Archive vs. PKZip vs. WinCC Duplicator

The following table compares backup utilities, target scopes, and failure risks across PCS 7 components:

Backup MethodIntended ApplicationHandles WinCC SQL DBs?Preserves Multiproject Links?Risk / Major LimitationSIMATIC Manager ArchiveFull PCS 7 Multiproject BackupYes (if WinCC is closed)Yes (100% integrity)Fails if runtime is active or disk fullManual 7-Zip / PKZipRaw file compressionNo (skips locked SQL files)Yes (file paths only)Corrupts SQL databases if lockedWinCC Project DuplicatorOS Redundant Server SyncYesNo (destroys PCS 7 links)Never use for multiproject backupsCopy Project Tool (WinCC)Standalone WinCC project copyYesNoDecouples project from SIMATIC ManagerProcess Historian BackupLong-term PH/CAS data backupYes (native SQL backups)N/ADedicated to historical archives only

Step-by-Step Procedure for Reliable Multiproject Archiving

To create a clean, uncorrupted archive of a PCS 7 multiproject:

Deactivate Runtime and Close Engineering Editors:
- On all redundant OS servers and clients, deactivate WinCC Runtime (Deactivate Runtime).
- Wait until WinCC Runtime completely unloads from memory (verify in Windows Task Manager that CCRtSys.exe is terminated).
- Close WinCC Explorer on all machines.
- Close all CFC charts, SFC editors, and HW Config windows on the Engineering Station.
Purge Temporary Runtime Cache and Historical Files:
- In Windows Explorer, browse to each OS project directory.
- Check the ArchiveManager folder. If historical archives do not need to be retained in the engineering backup, back them up separately or exclude them.
- Delete any temporary runtime database files matching <ProjectName>R.mdf and <ProjectName>R.ldf (these are temporary files created during runtime).
Execute SIMATIC Manager Archive:
- In SIMATIC Manager, select the top-level Multiproject icon in the tree.
- Select File -> Archive.
- In the Archive dialog, select the Multiproject tab and ensure the entire multiproject is checked.
- In the target selection dialog, specify a local hard drive (e.g., D:\PCS7_Backups\) rather than a network share.
- Select the archive format (.zip or .pkz) and click OK.
- Wait for the progress bar to complete without interrupting the workstation.
Copy Archive to Secondary Secure Storage:
- Once the local archive completes cleanly, copy the resulting .zip file across the network to your enterprise NAS or backup server.

Verification

Verify archive integrity:
1. Perform a test restoration: In SIMATIC Manager, select File -> Retrieve.
2. Point to the newly created archive and retrieve it into a temporary test directory (e.g., D:\Test_Restore\).
3. Confirm that SIMATIC Manager retrieves all AS projects, the Master Data Library, and OS projects without checksum errors.
4. Open the retrieved OS project in WinCC Explorer; confirm that the project database opens cleanly and the WinCC Graphics Designer displays all pictures.

Limitations and Operational Precautions

Never Archive While Runtime is Active: Archiving while WinCC is in runtime creates an inconsistent SQL snapshot that cannot be re-attached upon retrieval.
Avoid Third-Party Archivers on Active Folders: Do not use Windows Explorer built-in zip or 7-Zip directly on the project folders while SIMATIC Manager is running, as internal database lock files (*.lck) will be captured.
Disk Space Allocation: The target drive must have free space equal to at least 2.5 times the uncompressed project size to accommodate temporary compression cache.

Engineer FAQ

Can I use WinCC Project Duplicator to make a backup of my PCS 7 project?

No. The WinCC Project Duplicator is only for synchronizing redundant servers. Using it for backups breaks PCS 7 multiproject integration.

Why does WinCC fail to open after retrieving an archived project?

This occurs if the project was archived while WinCC Runtime was active or if SQL Server files were locked during compression, causing database corruption.

What is the difference between a .zip and a .pkz file in SIMATIC Manager?

Both use standard PKZip compression. A .pkz file is a renamed .zip file designated specifically for SIMATIC multiprojects and package libraries.

Should I include the ArchiveManager folder in my multiproject archive?

Generally no. Historical data in ArchiveManager can be hundreds of gigabytes. Long-term historical data should be archived separately via Process Historian.