Thanks for posting in the Community! Just to make sure that we are on the same page please review our basic troubleshooting steps (in English) with Visio import from the Lucid Community and let me know if you have any questions.

Can you verify that the file is able to be opened correctly in Visio? If a file is the wrong file type or has some other issue that makes it an invalid file Lucidchart will not be able to import it.

If you are able to open the file in Visio please try saving using the VSD file format then importing that file to Lucidchart. Switching the file type can sometimes correct issues in the file itself.

If this does not work please reach out to us directly at support@lucidchart.com--we would be happy to take a closer look. Please include the Visio file and a screenshot of what you are seeing on your end in your message. Cheers!