I have a Half-Life 2 video recording of me playing a section in "Sandtraps" chapter for completing a "Step Off The Sand" achievement.

I would like to have it as an individual .mp4 video, but the export doesn't work for me. No matter what name I give the file, no matter what location I give it, no matter what additional parameters I set... Steam refuses to export the recording and gives me the same, vague error message.

"Failed to export, try again (10)"

What's also interesting is that it first gave me the same error with (2) number the first time I pressed the "Export Video" button.

I tried to google-search both these errors, but I found no solution so far.

I would like to receive some help on that. Thank you so much.