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An Activity Log is required for support requests. Please read How-to get an activity log? for details on how and why this should be provided.
https://www.dropbox.com/s/7mfacfyf35ek6ug/Handbrake%20activityPDF.pdf?dl=0
Please replace this text with the contents of your log file between the two code tags - OR - provide a pastebin URL in place of these 3 lines.
You need to add .mp4 to the file name. Click once on the file to select it, press return to rename it, press the right arrow key to set the insertion point to the end, type .mp4, then press return to finish.
HandBrake typically adds .mp4 for you automatically but it looks like you accidentally removed it when you named the destination in HandBrake.
Same thing in today's world. Old versions of iTunes and old firmware wouldn't recognize certain features without that extension, but that time has essentially passed.