Blank lbr2 file

I designed (15 days of work) the file in LB and recorded it on an external SSD disk. It is 7.1 MB big. I do not synchronize copy on NAS or something similar. In the meantime, I updated LB to 1.7.03.
The next day I opened the LB file by double-clicking on it. It opened but I couldn’t see anything inside. In Windows Explorer, when I highlight the file, it shows a preview of the whole file.
I reinstalled LB to an older version but still file isn’t visible.
While Importing or dragging and dropping, still can’t see the file.
I tried to open it on a second PC, also Win 10 and v. 1.7.03. but still nothing happened.
Thanks in advance.

Can you please send us the file by uploading it here?

Check you have not turned off “show” in the cuts and layers tab.