Seems there’s a rash of this going on of late:
Maybe @colin and the Dev Team can work some kind of miracle.
I tried opening the file on my end and got the same result as the linked forum post. The only difference is I can see something of a preview of the image when it’s on my desktop.
As for the rest, when I open it, I get the error message, and when I click “ok” SketchUp proceeds to open as “Untitled” with these two weird little pulldown menus in the upper left corner. If I click on them, I get a bugsplat report.
I’m wondering if an extension is responsible… it might explain those weird pulldown windows. What extensions do you typically have going while you work?
Also, have you saved your work to Trimble Connect? If so, you can typically see a version history and try opening an earlier version of the file. If not, it’s in the developers’ hands and there’s a very real possibility you’ll have to start over.