How to fix Error 8515 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: SQL Server Error 8515 – MS DTC Global State Is Not Valid

Why This Error Happens

Error 8515 occurs when SQL Server attempts to execute a distributed transaction, but the Microsoft Distributed Transaction Coordinator (MS DTC) service is either not running, not properly configured, or cannot communicate due to security/network restrictions. This is commonly caused by the DTC service being disabled, network DTC access being turned off, or firewall rules blocking the RPC ports required for distributed transaction coordination between servers.

Step-by-Step Resolution Guide

Step 1: Verify and Start the MS DTC Service

  • Open Run (Win + R) and type services.msc.
  • Locate Distributed Transaction Coordinator in the services list.
  • Ensure the Startup Type is set to Automatic.
  • Right-click and select Start if the service is not running.
  • Alternatively, use PowerShell: Start-Service -Name MSDTC

Step 2: Enable Network DTC Access

  • Open Component Services by typing dcomcnfg in the Run dialog.
  • Navigate to: Component Services > Computers > My Computer > Distributed Transaction Coordinator > Local DTC.
  • Right-click Local DTC and select Properties.
  • Under the Security tab, check the following boxes:
  • Network DTC Access
  • Allow Remote Clients (if applicable)
  • Allow Inbound and Allow Outbound
  • Enable XA Transactions (if using cross-platform transactions)
  • Click Apply, then restart the MSDTC service when prompted.

Step 3: Configure Windows Firewall Rules

  • Open Windows Defender Firewall with Advanced Security.
  • Create an Inbound Rule and Outbound Rule to allow msdtc.exe (typically located at C:\Windows\System32\msdtc.exe).
  • Ensure RPC port 135 is open for both inbound and outbound traffic.
  • If using a fixed port for DTC, configure it via registry at:
    HKEY_LOCAL_MACHINE\Software\Microsoft\Rpc\DCOM Protocols

Step 4: Synchronize DTC Settings Across Servers

  • If this is a distributed transaction between two SQL Server instances, repeat Steps 1–3 on both the local and remote servers.
  • Confirm that both servers can resolve each other via DNS or hostname.
  • Restart the SQL Server service on both instances after DTC changes are applied.

Alternative or Verification Steps

  • Run DTCPing or the built-in DTC Tester tool (Component Services > Local DTC > right-click > Properties > Tracing) to confirm connectivity between servers.
  • If the issue persists, check the Windows Event Viewer (Application and System logs) for specific MSDTC-related errors (Event ID 4097 or 4098) to pinpoint configuration mismatches.