Hi
I hope you can find a fix for this issue as i do have loads of m4a files, many of my files are itunes purchases.
Sometimes i do tend to go back to enter tag on old tracks and by the time I write the tags to files, it removes all tags that i previously added to the label field.
As a work around i have now mapped to add the tag to comment fields as well, but i use my comment field for other personal tags that i don’t necessarily want to include in my global tag list.
No worries, I’m sure I can fix it
Should be fixed in todays update
Tested and works great now. Thanks for the expedient fix as usual.
Came across this again with the remixer field
I have star rating mapped to “remixer” and its not writing to it.
Its even emptying the ones i manually did in Serato
Let me know if you need the files
Yes please, files would be great! About to do a beta update so would be nice to get this in there too 
Sent your way.
m4a
Serato doesn’t actually store remixer in the m4a file, but in the database. The (unofficial) remixer ID3 tag for m4a is an iTunes tag that Serato seems to ignore.
So writing tags to file will not work for M4A files and the remixer field and then reloading tags in Serato.
What does work is to sync to Serato, then Lexicon puts remixer in the Serato database.
Oh I see! Thanks for checking it out!
When I do write things to remixer tag in Serato, if I use kid3 or any other tag reader I see what I write there.
So I’m confused 
Yeah kid3 reads the iTunes remixer field and most ID3 programs do the same. Serato does not…
Just so that I can understand better, Serato can write to m4a remixer tag but can’t read it?
From my testing here, it seems Serato doesn’t write remixer to the m4a file but only the database. Basically, Serato doesn’t do m4a remixer field, read or write
gotcha, I did some testing here and you are absolutely spot on.
I’m going to have to decide on another tag to use for the thousands of m4a.
