Three weeks or so ago, I asked for help getting my iTunes library to work on my new mobile phone (a Samsung Galaxy s10e). I got a load of helpful advice and I’ve now got myself a big sd card and loaded my tunes onto it. When I access the phone from File Explorer on my PC, I can see that all the files are there and I can play them on the PC from the phone’s storage files. So far so good.
Some of the music files work fine on my phone but the ones that I have uploaded to my PC in the last four or five years won’t play. I’ve tried MediaMonkey, Google Play Music and the Samsung Music player but none of them display the music files in question in their listings (neither the tracks nor the albums they’re on). I can see them in My Files on the phone (and they are made up of the right amount of data – they aren’t just empty titles) but can’t get them to play on any of the players from there. I don’t get an error message from the first 2 players and the Samsung one tells me the player doesn’t support this kind of file. But the files in question are M4A files and so are the ones that the players will play. So why does the phone/all the players have a problem with recently uploaded M4A files but not older ones?
Does anyone have any suggestions for how to fix this? All help gratefully received.

DRM issue? Older iTMS purchases had DRM.
These aren’t iTunes purchases. They are CDs that I copied onto my PC using iTunes. And they are new, not old.
That is odd. Try installing VLC Media Player on the PC and the phone, and try playing them in that on both devices.
Also have a look at the tags in mp3tag on the PC and see if there’s anything which looks funny. Is there a protection flag set?
That’s amazing! VLC can locate and play all of my music. Thank you so much @fentonsteve!
But how did you know that would work?
I had a look at the metadata in a lot of the files on the PC and couldn’t find any differences between the files that played and those that didn’t. But I guess it doesn’t matter now. I have a player that will play my music and I’m a happy man. Thank you so much!
VLC is ported to Windows by the Linux team and is as format-agnostic as you can get. If VLC can’t play it, it probably can’t be played.
In videoworld, we used to say that if VLC wouldn’t play it then there was definitely something wrong. Less so these days but still a very useful tool.
You could try a freebie file format converter and convert the lot to MP3. I’ve had problems with M4a occasionally which at the end of the day of an Apple proprietary format where MP3 is standard. I like NCH for utility type things.
https://www.nch.com.au/switch/mp3.html
Incidentally I discovered recently that the timing of a track is buggered up by MP3 when importing some parts into a recording which the other guy had sent as MP3s but were clearly out of time with the other parts. Some experimenting and research revealed that the M4A algorithm locks down tempo but MP3 doesn’t. Nerdier still, Logic can cope with this but my recording software, Reaper, doesn’t. Further, Reaper won’t open M4A files anyway. So it’s .WAV all the way for me. @fentonsteve may be the only person who has read this far.
Well I read it all and I’m very happy that @fentonsteve‘s suggestion has solved my problem. But thanks for taking the time and trouble to reply.
Brilliant well done. Just glad you got it sorted. I use VLC media player on my laptop and it’s excellent.
Yeah. I only chose MediaMonkey over VLC because someone recommended it in response to my previous cry for help. VLC is clearly absolutely fine. Amazing how solving problems like this (or having someone do so for you) can make your day!
I think MM is better for playlists, iPod sync etc but if it won’t play the bleedin’ songs that’s not a lot of help!
In MM, make sure all the input plugins are present for the files you have and they are selected in the file types listing under Tools>Options. Extra plugins are available for download.
Phwoar, you know how to get my glasses steamed up, Twang. In case you needed reminding, I am very dull.
I thought that would put lead in your pencil.
VLC has a built-in file converter, but I’ve never needed to use it.
Presumably any file it can load and play can be converted but I don’t know what formats it outputs to.
I tend to use Foobar 2000, another Linux port, for conversion duties, which has hundreds of plugins for all kinds of weird file formats. But you need an engineering degree to understand the settings and options. Luckily, I have one of those.
I use Faasoft Audio Converter for audio file conversion, it converts pretty much everything to pretty much everything else, so you could use it to convert the problem files to whatever you need. It’s very quick and easy to use, and available for Windows as well as Mac. Costs $25, but I think is worth it.
On the subject of audio converters I have finally converted a whole load of flacs sent to me by a member of this parish, using freeac https://www.freac.org/ an open source converter which seems to work fine, and crucially handles batch conversion easily.
Batch conversion is good if a lot of stuff needs processing. A potential saving of lots of time and huge relief of tedium.
It’s possible (likely!) that no-one is interested but I thought I’d update on my latest progress.
Having established that VLC (but not other apps) would play all the tracks that I had dumped onto the SD card on my phone by a simple copy and paste, I deleted everything from the SD card, opened up the Windows media player on my PC, pointed it at my music library and synced the library with the SD card. So the music is back on the phone and this time I can play all of it with MediaMonkey – including the tracks that MediaMonkey didn’t recognise previously.
I didn’t do any file conversion, just used the standard sync settings.
Better and better. Thanks again to everyone for their comments.
That stinks of “can play on this device only” iTunes DRM-ness.
Media Monkey and the other media players I know of won’t play DRM-protected files, but I thought both WMP and iTunes didn’t use DRM any more. Only really old media files would be DRM-protected.
To be clear you synced it with Media Monkey?
I assumed he meant he used WMP to sync the files with the card and then Media Monkey just read them from the card.
Ah yes rereading it I agree.
Sorry for not replying before. I’ve been away. @Mike_H is spot on.