How to Fix Error 256:72 'Unable to Close Table YDBS/YLinklist' During Project Reorganization in SIMATIC STEP 7

In SIMATIC STEP 7 and PCS 7, the error 'Link management: unable to close the table .../Project/YDBS/YLinklist, Error code: 256:72' during a 'File > Save As with Reorganization (Slow)' occurs because the Y-Link database file (YLNKLIST.DBF) is actively locked by a lingering background Windows process or an orphaned database lock file (.lck / .dbf__tmp) resulting from a previous software crash. Deleting YLNKLIST.DBF must NEVER be attempted, as it permanently corrupts the project symbol table and hardware cross-reference links. To resolve this cleanly, close all SIMATIC applications, terminate lingering 's7*.exe' processes in Task Manager, delete temporary '.dbf__tmp' files in the YDBS directory, and reorganize to a new destination folder.

Architecture of the YDBS Folder and YLinklist Database Files

In SIMATIC STEP 7 and PCS 7 multi-projects, the project directory structure relies on proprietary relational database tables:
* The YDBS Directory: Located at [Project_Path]\YDBS\. This folder houses the core database tables managing the Symbol Table, Hardware Cross-References, and Y-Link / Redundant DP Master Link Management.
* The YLNKLIST.DBF Table: Stores internal cross-reference records mapping redundant PROFIBUS DP lines, Y-Couplers, and redundant bus interface modules (IM 153-2).
* Why Reorganization Locks Occur:
* During File > Save As with Reorganization (Slow), STEP 7 opens every internal .dbf database table, purges deleted records, recalculates indexing b-trees, and repacks tables.
* If any Windows process holds an open file handle on YLNKLIST.DBF, the reorganization engine cannot gain exclusive lock rights, triggering: Error code 256:72 Link management: unable to close the table .../Project/YDBS/YLinklist.

The Fatal Trap of Deleting YLNKLIST.DBF

When frustrated engineers encounter table lock errors, they sometimes delete YLNKLIST.DBF in Windows Explorer:

The Catastrophic Outcome:
YLNKLIST.DBF is not a temporary cache file; it is a foundational schema component.
Deleting it permanently corrupts the STEP 7 data management layer.
The project Symbol Table becomes completely defective and inaccessible.
Re-opening the project produces errors such as: Symbol table could not be initialized, and HW Config consistency checks will permanently fail.
The Golden Rule: Never manually delete .dbf files inside the YDBS folder. Only temporary lock files (.lck, *.tmp, *.dbf__tmp) may be purged.

Identifying Lingering Background Processes and Stale Lock Files

To release the lock on YLNKLIST.DBF:

Terminate Hidden STEP 7 Processes:
* Close SIMATIC Manager.
* Open Windows Task Manager: inspect the Details / Processes tab.
* Locate and terminate lingering background processes:
- s7tgtopx.exe (SIMATIC Manager background engine)
- s7oemax.exe (Automation object engine)
- s7ubtstx.exe (Symbol table editor daemon)
- s7hcompx.exe (HW Config compiler)
- pdlrt.exe / CCApp.exe (WinCC background tasks)
Purge Stale Temporary Files in Windows Explorer:
* In Windows Explorer, browse to [Project_Path]\YDBS\.
* Search for files ending with:
- *.dbf__tmp
- *.tmp
- *.lck
- These files represent orphaned locks created during earlier system crashes. Delete these temporary files safely.

Step-by-Step Clean Reorganization to a New Target Directory

Once all file locks are released, execute the reorganization to a clean destination directory:

Reboot or Log Off Windows:
* Logging off Windows guarantees that all orphaned DCOM handles and SQL Server locks are flushed.
Launch SIMATIC Manager:
* Open SIMATIC Manager. Open the problematic project.
Execute Reorganization to a New Path:
* Select File > Save As....
* Check the box: With reorganization (slow).
* Under Name, assign a new project name or select a fresh target folder on drive C:\ or D:\ (e.g., D:\Projects\Project_Clean).
* Click OK.
Reorganization Execution:
* STEP 7 rebuilds all relational tables, purges dead memory pointers, and outputs a perfectly compressed, 100% consistent project.

Comparison of Project Reorganization Methods and Error Signatures

The table below outlines project save and reorganization modes in SIMATIC STEP 7.

Reorganization ModeDatabase ActionImpact on Deleted BlocksResolves File Corruption?Typical DurationSave As (Normal)Copies files verbatimRetains deleted block ghost recordsNo30 to 60 secondsSave As with Reorganization (Slow)Rebuilds and repacks all DBF tablesPermanently purges ghost recordsYes (Full database repair)5 to 20 minutesDeleting YLNKLIST.DBFDestroys database schemaCorrupts Symbol Table completelyNO - Destroys Project!Instant destructionPurging .dbf__tmp / .lckRemoves stale lock pointersUnlocks tables for reorganizationYes1 minute

Verification

To confirm that the project database is fully repaired and consistent:
1. In SIMATIC Manager, open the newly saved, reorganized project.
2. Open the Symbol Table: confirm that all symbol names, data types, and comments display cleanly without corruption warnings.
3. Open HW Config for all automation stations: execute Station > Check Consistency. Verify 0 Errors, 0 Warnings.
4. Open the CFC chart folder: perform a compilation check (Chart > Compile > Changes Only). Confirm compilation succeeds without database linkage errors.
5. In Windows Explorer, verify that the project folder size is reduced and no *.lck or *.tmp files exist in the YDBS directory.

Limitations and Operational Precautions

Never perform 'Save As with Reorganization' across a high-latency network share or wireless connection; database reorganization requires intensive local disk I/O.
Always maintain a timestamped zip archive of the multi-project before initiating reorganization.
Ensure sufficient free disk space exists on the destination drive (at least twice the size of the original project).
Always validate final software licensing, engineering station prerequisites, and backup procedures against the applicable Siemens catalog and authorized distributor quotation.

Engineer FAQ

Why did deleting YLNKLIST.DBF destroy my symbol table?

YLNKLIST.DBF contains internal schema definitions linking symbols and hardware objects. Without it, STEP 7 cannot decode the binary symbol pointers, rendering the symbol table unreadable.

How can I recover if someone already deleted YLNKLIST.DBF?

You must restore the project from a recent backup archive (.zip). If no backup exists, you can attempt to copy an empty YLNKLIST.DBF from a freshly created dummy STEP 7 project, though symbol cross-references may require manual re-linking.

What is the difference between fast and slow reorganization?

Fast save merely copies files including dead space and deleted block remnants. Slow reorganization reads each record, purges deleted blocks, rebuilds database indexes, and creates a compact, optimized database structure.