#8433 Video file selection required

This means the software did not detect any valid selected video/audio file when you clicked Start Execution, so the task was blocked at the validation step and never started.

Solution:

1. Click the Select Video/Audio button in the upper-left corner and pick a file with a supported extension (mp4/mkv/avi/mov/wav/mp3). If you want to batch-process an entire directory, check Folder first and then select the folder.
2. Make sure the selected file is a physical file already extracted to disk, not a file opened directly inside a compressed archive.
3. Rename the file to a short name containing only English letters and digits (e.g. video1.mp4) and move it to a shallow directory (e.g. D:/videotrans), removing emoji and special symbols from the name and path; otherwise the file may fail to be recognized or later FFmpeg steps will report errors.
4. In Windows, enable View → File name extensions in a folder to confirm you selected a real video file rather than a same-named subtitle or text file.
5. Confirm that the file actually contains an audio track with human speech, then click Start Execution again.

If you have clearly selected a valid video and still get this prompt, the cause cannot be determined from the current information. Please provide the last 30 lines of the latest log file in the logs/ folder under the software installation directory (copied together with the error stack) for analysis.