Inquiry Regarding Compatibility of Excel Add-in with 32-bit Office

Skip to first unread message

Sham Khole

May 10, 2024, 8:00:44 AMMay 10
to Excel-DNA

I am reaching out to discuss an issue I encountered while developing an Excel add-in using .NET Framework C# and integrating it with Excel Dna. Currently, the add-in functions seamlessly with 64-bit versions of Excel Office; however, I have encountered compatibility issues with 32-bit versions and shows below issue.

Given this situation, I am seeking guidance on how to ensure that the add-in is compatible with both 32-bit and 64-bit versions of Excel Office. I would appreciate it if you could provide insights or resources on how to resolve this compatibility issue effectively.

Additionally, if there are specific steps or adjustments that need to be made within the code or during the installation process to accommodate both versions of Excel Office, I would be grateful for your advice on that matter as well.


Govert van Drimmelen

May 10, 2024, 8:25:07 AMMay 10

Hi Sham,


When building your add-in, you’ll find two add-in the output  directory, and two in the ‘publish’ directory.

The add-ins are typically called <MyProject>-AddIn.xll and <MyProject>-AddIn64.xll in the output directory and then

<MyProject>-AddIn-Packed.xll and <MyProject>-AddIn64-Packed.xll in the publish directory.


These add-ins are for 32-bit (<MyProject>-AddIn.xll  / <MyProject>-AddIn-Packed.xll ) and 64-bit (<MyProject>-AddIn64.xll  / <MyProject>-AddIn64-Packed.xll) installations of Excel respectively.

You need to ensure that the right add-in is loaded or installed to match the Excel installation.



You received this message because you are subscribed to the Google Groups "Excel-DNA" group.
To unsubscribe from this group and stop receiving emails from it, send an email to
To view this discussion on the web visit


Sham Khole

May 13, 2024, 2:54:34 AMMay 13
to Excel-DNA

Hi Govert,

Thank you for your prompt response and clarification regarding the add-in deployment for both 32-bit and 64-bit versions of Excel Office.

Just to confirm my understanding, if I include all the mentioned files in the installer, namely <MyProject>-AddIn.xll, <MyProject>-AddIn64.xll, <MyProject>-AddIn-Packed.xll, and <MyProject>-AddIn64-Packed.xll, would this ensure compatibility with both 32-bit and 64-bit installations of Excel?

Your guidance is greatly appreciated.

Best regards, Sham

Govert van Drimmelen

May 13, 2024, 2:59:58 AMMay 13

Hi Sham,


The idea is that you set up the project so that the two -packed.xll files are the only files needed.

Then the non-packed add-ins (which need extra files to run) does not need to get distributed.


So you should first check that the two xxx-packed.xll do indeed work correctly as single-file add-ins.

Depending on your runtime target and dependencies, you might need to tune your project for this to work right.


One you know the single file .xll add-ins work, you need to set up your installer to register the correct one (32-bit or 64-bit) according to the machine where it is being installed. With the WixInstaller example, we have a “Custom Action” project, which is a small .NET assembly that is built as part of the installer. The custom action checks for the bitness of the Excel installation, and registers the appropriate version of the add-in.

Reply all
Reply to author
0 new messages