Resolving Central Archive Server (CAS) and StoragePlus Backup Halts Caused by Windows Event 1053

In SIMATIC PCS 7 systems utilizing Central Archive Server (CAS) or StoragePlus, backup operations halting while Archive Manager folders continue updating—accompanied by Windows Event ID 1053 ('Windows cannot determine the user or computer name. Not enough storage available to complete this operation')—is caused by Windows kernel memory or Desktop Heap exhaustion, not physical disk space exhaustion. Win32 error code 0x8 ('ERROR_NOT_ENOUGH_MEMORY') maps to the phrase 'Not enough storage', occurring when long-running SQL Server instances and StoragePlus services exhaust the non-paged memory pool or LSA security tokens. To recover, increase the Windows IRPStackSize and SharedSection Desktop Heap in the registry, verify DNS/NetBIOS resolution, and execute a planned system restart.

Architecture of CAS and StoragePlus Long-Term Archiving

In legacy SIMATIC PCS 7 installations (V7.0, V7.1, V8.0), historical long-term archiving of process values and alarms is managed by the Central Archive Server (CAS) powered by StoragePlus. CAS operates as a centralized data repository connected to redundant OS Servers across the Terminal Bus:

OS Server Swapping: OS Servers write circular archive segments locally. When a segment closes, WinCC swaps the archive to the CAS server over Microsoft Message Queuing (MSMQ) and SQL Server replication.
CAS Archive Manager: CAS mounts incoming database segments into its central Microsoft SQL Server catalog.
Automated Backup Engine: StoragePlus cyclically exports consolidated database packages into external backup destination folders (e.g. NAS storage, secondary hard drives, or tape libraries).

When CAS backup halts while Archive Manager continues to receive files, the core database ingestion remains functional, but the background export service fails during file system operations.

Decoding Windows Event ID 1053: Memory Pool vs Disk Space

When investigating failed backup jobs, engineers frequently examine Windows Event Viewer (Application log) and discover repeated occurrences of Event ID 1053:

Event ID: 1053
Source: Userenv
Description: Windows cannot determine the user or computer name.
(Not enough storage available to complete this operation).
Group policy processing aborted.

Engineers often respond by increasing physical hard drive space (e.g., expanding from 190 GB to 262 GB free space), only to find the error persists. This occurs because the Windows error string originates from internal Win32 error constant ERROR_NOT_ENOUGH_MEMORY (Code 8 / 0x00000008), which historically renders as 'Not enough storage is available to process this command'.

The following table distinguishes between physical disk storage and kernel memory bottlenecks:

Resource ClassificationSystem ParameterObserved Diagnostic SymptomUnderlying Architectural ConstraintPhysical StorageHard disk partition free bytesWinCC disk full warnings / SQL write stallsCAS backups halt even with 260+ GB free spaceDesktop HeapSharedSection User32 bufferEvent ID 1053, window creation failureDefault non-interactive heap (512 KB) depletedKernel I/O StackIRPStackSize packet depthNetwork share file transfer timeoutsDeep archive directory paths exhaust default stack (15)Security Token Cachelsass.exe credential poolGroup Policy abort, name lookup failureLong uptime without restart fragments kernel memory

In 32-bit Windows Server systems operating under continuous 24/7 industrial loads for 5+ years:

Desktop Heap Fragmentation: The Windows Local Security Authority Subsystem Service (lsass.exe) and User Profile service exhaust allocated Desktop Heap memory (SharedSection).
IRPStackSize Depletion: The server service runs out of I/O Request Packet stack locations when executing file transfers across network shares or deep partition directories.
NetBIOS / Kerberos Token Corruption: Windows cannot resolve its own security context to validate service account rights.

Step-by-Step Technical Remediation and Registry Tuning

To resolve Event 1053 and restore automated CAS / StoragePlus backups, execute the following technical remediation workflow:

Adjust Desktop Heap in Windows Registry: Open Registry Editor (regedit.exe) as Administrator. Navigate to:

HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\SubSystems

Locate the Windows key. In the value data string, locate the parameter SharedSection=1024,3072,512 (or similar). Increase the non-interactive desktop heap (the third value) from 512 to 1024 or 2048:

SharedSection=1024,3072,1024

Increase Server IRPStackSize: In the registry, navigate to:

HKLM\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters

Check for DWORD value IRPStackSize. If it does not exist, create a new DWORD (32-bit) named IRPStackSize. Set its decimal value to 30 (default is typically 15; valid range is 11 to 50).

Verify DNS and Computer Name Resolution: Open Command Prompt. Ping the local CAS computer name, the fully qualified domain name (FQDN), and the redundant CAS partner. Ensure forward and reverse DNS lookups resolve instantaneously without timeouts.
Execute Planned System Reboot: Perform a planned reboot of the CAS server during a maintenance window to flush fragmented kernel memory pools and instantiate new registry allocations.
Restart StoragePlus Services: Verify in services.msc that CCStoragePlusService and SQL Server (WINCC) start cleanly under their assigned administrator credentials.

Verification

Confirm that CAS backup functionality is fully restored through these diagnostic steps:

Windows Event Viewer Audit: Open Event Viewer -> Application. Verify that Event ID 1053 has ceased occurring and that Userenv logs successful Group Policy application.
StoragePlus System Configuration Check: Open the StoragePlus Administrator console. Verify that status indicators for Archive Manager, Catalog Database, and Backup Service display green active status.
Backup Folder Inspection: In Windows File Explorer, browse to the designated backup destination folder. Confirm that new timestamped backup archive packages (.dcf, .mdf, .ldf export files) are generated and update cyclically.

Limitations and Operational Precautions

When maintaining legacy CAS and StoragePlus installations, observe these operational guardrails:

Registry Backup Mandatory: Always export and back up registry keys (File -> Export) prior to editing kernel memory parameters.
Migration from Obsolete CAS to Process Historian: Siemens officially declared CAS and StoragePlus obsolete following PCS 7 V8.0. Modern facilities must plan migration to SIMATIC Process Historian (PH) and Information Server (IS) for scalable, 64-bit SQL archiving.
Redundant CAS Partner Symmetry: In redundant CAS architectures, ensure registry memory tuning and service configurations are applied symmetrically to both master and standby CAS servers.

Engineer FAQ

Why did adding 70 GB of hard drive space not fix 'Not enough storage available'?

The message is a misleading legacy Windows translation of Win32 error ERROR_NOT_ENOUGH_MEMORY (Code 8). It refers to internal RAM desktop heap and kernel memory buffers, not physical disk bytes.

What is the difference between CAS Archive Manager and CAS Backup?

Archive Manager ingests process archives from OS Servers and attaches them to SQL Server. Backup exports sealed historical archive segments to secondary storage for disaster recovery.