Problem saving edited video file

[jeanluc]

I recently installed Avidemux 2.6.6 (64 bits version for Windows) to correct the audio/video synchronization of many MP4 video files which I downloaded from YouTube (mostly anime).  At first all went well and I was able to correct the lip sync on at least a dozen files.  However, starting yesterday, I can no longer save the corrected files.  I still can properly sync the audio and video but, when I try to save the corrected file, I end up with the original uncorrected file instead.  I am really puzzled because I have not changed my procedure at all, which is as follows:

- Set "Video Output" and "Audio Output" to "Copy"
- Set "Output Format" to"MP4 Muxer"
- Click the folder icon on the top menu and open the file to be edited
- Once the file is running observe if sound is either ahead of picture or lags behind it
- Click the "Shift" box in the "Audio Output" menu
- if sound is ahead of picture, enter a positive amount of milliseconds (ms) delay (most often 100 to 500)
- If sound lags behind picture, enter a negative amount of ms delay
- Click "Stop/Pause" on the bottom commands and go back by dragging back the cursor of the video position indicator slide
- Click "Play" on the bottom command to resume video play and observe if audio/video synchronization has been properly corrected.
- If necessary make further adjustments by repeating the above 4 steps until you are satisfied that video and audio are in sync.
- Click "Stop/Pause" on the bottom commands and then "File" on the top menu
- Select "Save" in the drop down "File" menu.  A dialog box will open which allows you to select the name you want to give to the saved file and the location where you want to save that file. Once this is done, click "Save" in the dialog box.
- Open n the folder where  the corrected file has been saved and check that file.

Since yesterday, I have problems with the last two steps in that the file which is saved is not the properly synced corrected file but the out-of-sync original uncorrected file.

What am I doing wrong?   Any suggestions?  Please, help!

[mean]

What do you mean by since yesterday ?
You changed version ?

[jeanluc]

No, I didn't change version and I am not aware of having changed anything in my procedure either.  It simply is that, all of a sudden, I don't seem to be able to save the corrected file.