Why wont WMM save my project as a movie file?

This could be a lot of things.

What is your source material?
Have you tried exporting your movie using different settings or to a different destination drive?

Is there much editing and transitioning/effects? Or is it a pretty simple project?

Just WMV files. There’s a fair bit of editing and effects, more than usual. It’s just under 3 mins long. It now estimates 109 minutes, haven’t touched it since I asked the question here.

I would try a few things…

Try a simpler edit using the same source material.
Try moving the source material to another folder on the hard disk and re-import into your collections.
Try exporting to another destination, like a flashdrive.

I’ve imported everything needed onto another computer. I was a read-only file but after an automatic save (due to a WMM crash) it’s a normal file and seems to be having the same problem.
I started another project hoping that would save easier but I’m encountering the same problems as I was with the first one. (Loss of sound after about 25s). I used different source materials.

Thank you so much for helping.

Do you have a lot of photo (jpeg) files in the project? Are they very large file sizes? You might try optimizing your photos before inserting them in your project to keep the file size down.

No jpegs, only wmv and wma files.