sorry for the delay in answering. That warning can be ignored. The app always downloads the files with "tmp" extension and then they're renamed to the final name. E.g. we create a file named "myscorm.zip.tmp" and then we rename it to "myscorm.zip". We do it like this to prevent deleting the existing file if the download fails when updating a file that already exists. Some of our file system functions validate the extension and show a warning if it's not a valid one, that's why that message is displayed. We should probably stop showing the warning in this case.
I also see that warning in the console but the SCORM works fine in my Windows 10, so the error is caused by something else. One of the posts above mentions big SCORM packages, but the ones you sent us to test have a low size (2.5MB and 14MB). If those ones are failing for you it shouldn't be related to the SCORM size.
We still haven't been able to reproduce the issue, so unfortunately we can't provide a solution
We'll pay special attention to SCORM packages and Windows in our next release of the Moodle Desktop app.
I've been looking at a very similar issue, we've had some SCORM files that get stuck on the loading spinner and your patch from here appears to have fixed that (in the few I've just tested anyway)... https://github.com/moodlehq/moodleapp/pull/1545/commits/06bc1c1bfe413cd0dad011adf6cf353317d9b2aa
However, I have some larger SCORM files (>100MB) that are not getting past the "downloading" stage, with dev tools open in the electron app the debugger pauses saying it is about to run out of memory. Looking at the task manager I can see that the memory usage jumps up quickly just before this, in this case consuming several GB before I assume chrome kills it, which again I'm assuming is why the page then goes blank?
I'm not sure exactly where to go from here but hoping this might give a little more insight.