Learn about foreign files and how they are handled in Revit projects.
Foreign files are Revit files that were created through third-party applications, not with official Autodesk software products. These include, but are not limited to, project (*.RVT), family (*.RFT), or template (*.RTE) files.
While Revit can open foreign files, foreign files are not Autodesk software created files and Autodesk cannot and does not support them.
- Continue opening the file. Confirms that you understand that the file is a foreign file and continues to open the file. To stop the Open - Foreign File dialog from appearing again for this specific file, select Always open this file regardless of its origin.
- Cancel opening the file. Ceases opening the file and closes the Open - Foreign File dialog.
Foreign files always retain a reviewable foreign file notice, even if the Open - Foreign File dialog was suppressed. Click Manage tab 
Inquiry panel
(Review Warnings).
If you are working in a Revit project or family that is, itself foreign, reviewable foreign file notices do not display, because the only course of action would be to delete the file. Foreign file notices do display when a foreign file is added to your project so that it can be tracked and identified.