Resolving 'Cannot Start Database' Errors in PCS 7 Multi-User Engineering Environments

In SIMATIC PCS 7 multi-user engineering, the error dialog 'Cannot start database' when opening a shared multiproject over a network domain occurs when the local Sybase SQL Anywhere database engine (dbeng*.exe) cannot establish an exclusive lock or communication socket with the project database (amdbase.db). This failure is caused by stale background database processes from prior abnormal terminations, insufficient Windows share or NTFS permissions for domain engineering accounts, or network latency interrupting database keepalive packets. To resolve the error, terminate orphaned dbeng*.exe and s7tgtopx.exe processes in Windows Task Manager, ensure engineering accounts have Full Control on the shared project folder, and verify network connectivity.

Executive Summary

Multi-user engineering is an essential collaborative feature in SIMATIC PCS 7, enabling multiple automation engineers to edit independent user projects, CFC charts, and Master Data Libraries simultaneously within a central Multiproject hosted on a network server. A frequent operational obstacle is the sudden appearance of the modal warning Cannot start database when an engineer attempts to open the shared project. Clicking OK repeatedly sometimes permits the multiproject to load, but critical user projects, charts, or libraries appear missing, grayed out, or locked. Continuing engineering under this degraded state risks database corruption. This article analyzes the client-server database architecture of STEP 7, identifies the mechanics of lock contention, and provides verified remediation steps for enterprise engineering networks.

Architecture and Fundamental Mechanics

STEP 7 Sybase SQL Anywhere Engine, File Locking Architecture, and Multi-User Coordination:

The STEP 7 / PCS 7 Project Database Infrastructure:
Every PCS 7 project is backed by an embedded relational database engine: Sybase SQL Anywhere (Adaptive Server Anywhere).
The project database resides within the <ProjectName>\AMOBIJS\ directory as amdbase.db.
When an engineer opens a project in SIMATIC Manager, the application launches a local instance of the database personal server (dbeng16.exe in modern releases, or dbeng12.exe / rteng9.exe in older versions).
Multi-User File Locking Mechanics and Network Shares:
In a multi-user Multiproject environment, the multiproject root folder is shared across an SMB network share.
When User A opens User Project 1, their local dbeng*.exe process establishes an exclusive lock on UserProj1\AMOBIJS\amdbase.db.
When User B opens User Project 2, their local engine locks UserProj2\AMOBIJS\amdbase.db independently.
The Failure Vector: If User A's client machine experienced an improper shutdown, network blip, or crashed SIMATIC Manager session, the Windows file server may maintain an orphaned file lock on amdbase.db. Alternatively, an orphaned dbeng*.exe process may still be running in the background on the client PC, holding communication port 2638 and preventing the newly launched SIMATIC Manager from binding to the database engine.
Symptoms of Incomplete Loading:
If SIMATIC Manager times out attempting to contact the engine, it bypasses the locked user project to prevent total UI freeze, presenting an incomplete multiproject tree with missing folders or grayed-out S7 Programs.

Step-by-Step Implementation Procedure

Close SIMATIC Manager and Kill Orphaned Database Tasks on Client Workstations:
* Close SIMATIC Manager on the affected client machine.
* Press Ctrl + Shift + Esc to open Windows Task Manager; switch to the Details tab.
* Locate and terminate any running instances of:
- dbeng16.exe (or dbeng12.exe, rteng9.exe)
- s7tgtopx.exe (SIMATIC Manager UI host)
- s7cfcapp.exe (CFC Editor)
- ccprojgr.exe (WinCC project process)
Clear Stale Network File Locks on the Central Project Server:
* Log onto the server hosting the shared multiproject folder as Administrator.
* Open Computer Management (compmgmt.msc).
* Navigate to System Tools > Shared Folders > Open Files.
* Search the list for amdbase.db or files within the project path.
* Right-click any orphaned open files locked by disconnected user sessions and select Close Open File.
Verify Windows Domain and Folder Permissions:
* On the central server, right-click the shared Multiproject folder and select Properties.
* In the Sharing tab (Advanced Sharing), ensure the engineering domain group has Full Control.
* In the Security tab (NTFS Permissions), ensure the engineering domain group and local SIMATIC HMI group have Full Control.
Relaunch and Re-attach the Multiproject:
* On the client machine, launch SIMATIC Manager.
* Select File > Open, switch to the Multiproject tab, and browse to the UNC path (e.g. \\Server01\PCS7_Projects\My_MP.s7p).
* Confirm that the multiproject opens cleanly without 'Cannot start database' warnings, and verify that all user projects populate.

Verification

Open SIMATIC Manager on the client PC; verify that the multiproject tree displays all child projects, libraries, and AS stations.
Double-click any CFC chart inside a child project; verify that the chart opens in the CFC editor without database timeouts.
Verify in Windows Task Manager that a single instance of dbeng16.exe is running cleanly with low CPU utilization.

Limitations and Operational Precautions

Never attempt to edit CFC charts or compile S7 programs while user projects are in a partially loaded or missing state; modifying cross-chart interconnections in an incomplete multiproject can create unresolvable orphaned pointers in the S7 database.

Engineer FAQ

Why does 'Cannot start database' appear when opening a multiproject?

It indicates that SIMATIC Manager cannot communicate with the Sybase database engine due to stale file locks, orphaned background processes, or permission restrictions.

Should I continue working if the multiproject opens with missing projects after this error?

No! Close SIMATIC Manager immediately. Continuing to work with missing user projects can cause severe database corruption and broken interconnections.

What process runs the STEP 7 project database?

The Sybase SQL Anywhere personal server executable, typically named dbeng16.exe (or dbeng12.exe / rteng9.exe in older versions).

How do I clear locked database files on a shared network drive?

On the file server, open Computer Management > Shared Folders > Open Files, locate the locked amdbase.db file, and close it.

Can multi-user engineering operate over a VPN or Wi-Fi?

No. High network latency and packet loss over VPN or Wi-Fi cause Sybase engine keepalive timeouts and severe database locking faults. Use high-speed wired LAN only.