Corrupted MSP file

Hello,

While saving my main 6000 line schedule yesterday Microsoft Project corrupted my file. This is a very important working file for which I don't have recent backups.

When I try to open it, Project only shows me: "Project cannot open the file" I tried :

- to open it (read-only or not) with standard MSP 2019 (the one with which it was saved)

- to open it (read only or not) with MSP 2010 - to change the file extension to .mpt .mpd .mpx

- to insert this project in a new blank project

- to use an MSP file viewer

How to do ? Are there any file repair utilities? Other ?

thank you in advance for your help