File Unplayable

[TigerBlood52]

I have been digitizing old VHS tapes and saving them on a thumb drive. I have successfully saved around 10 hours of content so far. I think I made some unnecessary adjustments to the settings somewhere along the way, because now I get this error message upon attempted playback of all new recordings:

"This file isn't playable. That might be because the file type is unsupported, the file extension is incorrect, or the file is corrupt."

I have tried changing between file formats (MP4 and MKV), but that doesn't help.

Any ideas?

logfile:
15:41:05.363: ---------------------------------
15:41:05.363: [x264 encoder: 'streaming_h264'] preset: veryfast
15:41:05.363: [x264 encoder: 'streaming_h264'] settings:
15:41:05.363: rate_control: CBR
15:41:05.363: bitrate: 2500
15:41:05.363: buffer size: 2500
15:41:05.363: crf: 0
15:41:05.363: fps_num: 30
15:41:05.363: fps_den: 1
15:41:05.363: width: 1280
15:41:05.363: height: 720
15:41:05.363: keyint: 250
15:41:05.363:
15:41:05.368: ---------------------------------
15:41:05.369: [FFmpeg aac encoder: 'Track1'] bitrate: 160, channels: 2, channel_layout: 3
15:41:05.369:
15:41:05.416: ==== Recording Start ===============================================
15:41:05.416: [ffmpeg muxer: 'adv_file_output'] Writing file 'D:/VHS Videos MP4/2020-10-05 15-41-05.mkv'...
15:49:07.096: [ffmpeg muxer: 'adv_file_output'] Output of file 'D:/VHS Videos MP4/2020-10-05 15-41-05.mkv' stopped
15:49:07.096: Output 'adv_file_output': stopping
15:49:07.097: Output 'adv_file_output': Total frames output: 14427
15:49:07.097: Output 'adv_file_output': Total drawn frames: 14451
15:49:07.129: warning: 2 frames left in the queue on closing
15:49:07.129: ==== Recording Stop ================================================