File open failure, "not a diagram file"

[ozzynotwood]

When opening a file, error shows:
Not a diagram file (error on line 211 at column 1: Premature end of data in tag mxCell line 208)

To Reproduce
Steps to reproduce the behavior:
Open file directly in the desktop app OR by file association.

Expected behavior
File to open.

draw.io version (In the Help->About menu of the draw.io editor):
24.4.13

Desktop (please complete the following information):
Windoes, Desktop version of Drawio

Additional context
My drawio project saved normally. When I try to open the file the next day, I get the error stated above. I looked at the source code of the saved file & found the last 4 lines were missing:

I noticed this because I compared to a different file. When adding this lines in manually, the saved file was able to open. As I was able to open my document, make edits & save Monday then have the error appear on Tuesday I thinking there is a fault in the save process. I don't know if this is connected, but this happened around the same time I imported 2 PNG images to my project.

I would like a fix for this bug however look at the look it seems there have been file open issues for years. Can we at least have a method for recovering projects?

[davidjgraph]

Is your save folder a OneDrive sync folder?

[ozzynotwood]

Is your save folder a OneDrive sync folder?

No, this was on a flash drive.

[davidjgraph]

The latest desktop version has some functionality to improve loading of corrupted files. But overall, I'd avoid the use of a flash drive in this way. Saving from electron doesn't seem fully robust over less conventional media.