File Modified Dates updated Unnecessarily

I've noticed that if I have a group of files selected in the MP3Tag window and apply a change that only affects some, the Windows modified date/times for all the selected files are updated

I had a few files that had an extended tag set wrong, and rather that search one at a time, I selected the whole folder and set the proper tag, expecting that only a few files would be modified


  1. Copy a group of files to a temp folder (Comment field in all was blank)

  2. Apply MP3Tag to the folder and add a comment to one file

  3. Modify date for that file is updated

  4. Select all files

  5. Make Comment = and Save (ctrl-S)

  6. Modify dates for all files are updated

Doing a backup that compared modify dates to determine which files have change take a LOT longer since so many unchanged files are backed up

You have described the behaviour accurately.
Yet, MP3tag does not compare the already existing data with the modified but simply writes whatever it finds into the tags.
This means, that the files get actually rewritten even though you do not see a lot of difference between the current and the former state.
The only way around this would be to use filters or other selective mechanisms to pinpoint only those files that need the update.

The [Ctrl+S] command executed by the user acts as a forced storage against all selected files, therefore the underlying disk system changes the modified date time stamp as usual.

Within the dialog "Mp3tag/Tools/Options/Tags" you can advice Mp3tag to keep the "existing file modification time".


I suspected that it was just a case where the 'new values' were forced in, even if the value was already there

As suggestion, it would be very nice if the current tag value(s) were checked against the potential new tag value(s) and only if necessary rewrite the file

Since I didn't realize the way it worked, I had 25GB-30GB of MP4s that had to be backed up since I globally applied 'Movie' to a folder that only had 2-3 incorrectly tagged files

Thanks, but unfortunately my backup program goes by modification date and it would miss them :frowning: