How to Fix DCOM Error 80070005 in .NET Office Applications
Question details
Users need to resolve a DCOM access denied error when automating Word or Excel on a server environment.
- Product
- .NET Office Automation
- Device & OS
- Windows Server
- Scenario
- Automating Microsoft Word or Excel server-side via .NET applications and IIS.
- Observed behavior
- The application throws DCOM Error 80070005, indicating that access is denied due to application isolation, missing permissions, or server-side resource conflicts.
Ensure you have administrative privileges on the Windows Server to modify Component Services and DCOM configuration settings.
Adjust DCOM Permissions in Component Services
Grant the necessary launch and activation permissions to the application pool identity in the DCOM configuration.
This error typically occurs because the IIS Application Pool identity lacks the necessary permissions to launch and activate COM components like Word or Excel.
Press Win + R, type 'dcomcnfg', and press Enter to open the Component Services window.
Navigate to Component Services > Computers > My Computer > DCOM Config. Scroll down to find 'Microsoft Excel Application' or 'Microsoft Word Document'.
Right-click the specific Office application and select 'Properties'.
Go to the 'Security' tab. Under 'Launch and Activation Permissions', select 'Customize' and click 'Edit'.
Add the IIS AppPool identity (or your specific service account) and check the boxes for 'Local Launch' and 'Local Activation'. Click OK to save the changes.
Seek Expert Assistance on Microsoft Q&A
Consult specialized forums for complex server-side automation issues that basic permission adjustments cannot fix.
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Frequently Asked Questions
Why does Microsoft Office automation fail with error 80070005 on IIS?
Error 80070005 stands for 'Access Denied.' When running .NET automation through IIS, the application pool identity running the code typically lacks the necessary permissions to launch and activate COM components like Microsoft Word or Excel.
Is server-side automation of Microsoft Office supported?
Microsoft strongly recommends against server-side automation of Office applications. It is officially unsupported and can lead to instability, deadlocks, and permission errors like DCOM 80070005.
How do I find the correct Office application in DCOM Config?
Open Component Services (dcomcnfg) and look for 'Microsoft Excel Application' or 'Microsoft Word 97 - 2003 Document' in the DCOM Config folder. If they are missing on a 64-bit server, you may need to open the 32-bit Component Services console by running 'mmc comexp.msc /32' in the Run dialog.
