YTDM opens and closes immediately
Open Command Prompt inside the YTDM folder and run YTDM.bat. This keeps error output visible. Confirm that the complete Core and Scripts folders are present.
FFmpeg or FFprobe is missing
Confirm that ffmpeg.exe and ffprobe.exe exist in the Tools folder. Open Program Status, then use the Tools Updater if needed.
Video and audio were not merged
This usually means FFmpeg was unavailable or post-processing failed. Restore the bundled tools and retry the download.
Browser cookies cannot be copied
Close every browser window and background browser process, then retry. Public downloads can continue without cookies when authentication is not required.
A queue item failed
The failed item remains available for retry. Review the error log, verify the URL, update yt-dlp, and run the item again.
JavaScript runtime warning
Some YouTube extraction paths may benefit from a supported JavaScript runtime. Install a supported runtime such as Node.js when yt-dlp explicitly requests one.