Version: Revit 2023 and later.

Issue:

Revit fails to initialize the add-in when launching, displaying the following message repeatedly multiple times:

"Failed to initialize the add-in [add-in name] because the assembly [path to DLL] does not exist."

The path to the DLL points to a non-existing drive or a custom drive where it was previously installed. Even after a clean uninstall and re-installation of Revit, the issue persists.

Causes:

This issue arises from a previous Revit installation with custom settings. If the reinstallation of Revit is set to a different drive from the one used for the previous installation, a clean uninstall may not resolve the issue. Following the instructions on the links below does not resolve the issue either:

• "Failed to initialize the add-in [add-in name] because the assembly [path to DLL] does not exist" when launching Revit (autodesk.com)
• 2023: How to Complete a Clean Uninstall of Revit products (autodesk.com)

Solution:

To resolve the issue during the clean uninstall process, additional steps are required.

1. Use the Microsoft Uninstallation troubleshooter tool to ensure the removal of all relevant Revit support tools, including schemas, material libraries, texture packages, and add-ins. Note that you may need to run the Microsoft Uninstallation tool multiple times as it only removes one software at a time.
2. After completing the removal of the specific Revit version and all associated tools, navigate to the following folder locations and delete them:
   • C:\Program Files\Autodesk\Revit [Version]
   • C:\ProgramData\Autodesk\RVT [Version]
   • C:\ProgramData\Autodesk\Revit\Addins[Version]
   • C:\Users%USERNAME%\AppData\Local\Autodesk\Revit\Autodesk Revit [Version]
   • C:\Users%USERNAME%\AppData\Roaming\Autodesk\Revit\Autodesk Revit [Version]
3. Follow the remaining steps outlined in the guide "2023: How to Complete a Clean Uninstall of Revit products (autodesk.com)" to complete the uninstallation process.
4. Download the new Revit installation package from the Autodesk Product page under your account.
5. Reinstall Revit and apply the latest update to complete the installation process.

About the Author

Sr Technical Support Specialist<br><br> Skilled in AutoCAD, Mixed-use, Renovation, Revit, and Sustainable Design. Strong arts and design professional with a BA in Urban design focused in Architecture from University of Washington.

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