Prime 4 reboot on loading tracks

Hi there! Hope I’ll find a solution here for this huge problem.

It’s been like two weeks that my Prime 4 literally reboots when I select certain tracks of my collection (files running through external HD). The uploading of the file stops and the console reboots. All the crates and playlists work perfectly, even with the speed of loading and everything, but I noticed that when I choose certain songs it literally stops working (By now I spotted 2 of them for example, both little audio files with same metadata of every other track). Also, if I try playing it in Engine Prime on my computer the program stops responding.

I’ll be grateful to everybody who will help me out… thanks in advance!


Since the problem only occurs with some tracks and you got it both on the console and on the PC, it is evident that those MP3 files have some incompatibility problem. You could use software that checks the MP3 if it is damaged.


It is obvious that the problem is the tracks.

Buy them on a digital platform or ask a friend to pass them on to you (wink, wink)

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Correct, crashing the OS on players everytime a corrupt media file is played is unacceptable.

But… “if I try playing it in Engine Prime on my computer the program stops responding”

Thanks for the answer. Of course I tried to scan some errors in the mp3 files but everything looks fine. In fact both tracks for example are perfectly working on Rekordbox. That’s really weird.

Burn the tracks onto a CD-R then rip them into your collection with a really well known ripper that has a good reputation.

Add your own tags to the files manually, so you know you’re not adding any odd characters in the tags or the file names, add some conservatively sized album art if you wish,

The re-ripping process will get rid of any nasties from the original encoding


In fact, that’s the real issue. I can dig loading problems with loss of time while doing it, but I can’t accept a freeze and reboot of the whole system. The console stopped 2 times during a party while I was trying to understand the real reason…

Also, as I said up in another reply, after scanning them I found out that the tracks are perfectly fine and work normally on Rekordbox, both on computer and Pioneer CDJs.

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I’m having this issue also. This is unacceptable from a media player, no matter how “corrupt” the files are (files I haven’t had any issue with on any other device). Denon really need to address this.

I’ve the whole system freezing momentarily when plugging in my usb or loading some tracks, and the system has been rebooting. This has happened more with my new 256 gb usb which may be a factor, but the tracks will play afgter the reboot so I severely doubt it is an issue with the files themselves. The system restarting is simply unacceptable in any scenario, no matter if the usb is slow or the files used.


UPDATE: it happened again last night. Another track, another mp3 analysis that looks totally fine. I really should fix this problem, still don’t know how.

Because you said it’s an external drive, I’d suggest trying with a USB flash drive, an SD card or another drive. I’ve had my Prime 4 for around a year now, and I’ve used it for between three and five hours of continuous streaming several times a week - and it’s never rebooted when I’ve loaded a file.

I’ve got a lot of files, of all sorts of bit rates, from all sorts of sources, collected over decades. The audio has glitched on some (which have been promptly replaced) but nothing more serious than that.

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Good suggestion here. If your hard drive is going bad it will begin to corrupt files. I’d get those drives tested. If you find any bad sectors, replace the drive ASAP.

Circa 2 settimane fa’ ho riscontrato lo stesso problema…ho scritto anche nel forum…ho fatto persino un downgrade versione 1.6.0 e 1.6.1 ma nulla il problema si ripresenta blocco totale della console riavvio… Spero che DENON RISOLVI AL PIU’ PRESTO QUESTA GRAVE PROBLEMATICA.

The first thing I would say is please don’t try and fix the files without uploading them to Denon DJ.

There is a method to get these tracks uploaded so the developers can find out why these tracks have crashed the system. Garbage in the header or other junk in the file, even a character can be problematic. A corrupt file should just stop playing or refuse to load. We should never be at a stage where the whole unit reboots. The devs can build protections in to help reduce this from happening.

The Denon DJ devs will need to see what caused this and help fix it in the OS. Once that is done you can try fixing the file. We don’t want anything killing play at a festival or other big gig just because the DAW encoder wasn’t right etc.

I have successfully fixed files using these two apps:

  • Mp3val (Win)
  • MP3 scan + Repair (Mac)

Give them a go and you’ll be amazed as to what gunk they find, even from officially sourced tracks. I ran my entire collection through them and they found lots of junk that has fixed the lightning bolt in Serato DJ and a crash in a store purchased mp3 in Traktor.

Also, a read of this will help. Yes it’s Traktor but the rules still apply to any DJ software.


It’s possible to cause the Prime 4 to crash and hard reboot when trying to load a track with a ridiculously high BPM - I had a friend try to load a track from his USB that he had somehow set the track BPM to 20000 and it would cause the player to freeze and then reboot

I wonder if that’s caused by the player trying to map thousands of beatgrid markers?

After all, if a track is 120 bpm and it last 4 minutes then it’s only going to need 480 beat grid markers. But, if a 4 minute track is claiming to be 1000bpm then the firm/soft ware is going to try and place 4000 Beatgrid markers. That’s a lot of markers to keep track of, and there must be some sort of maximum capacity for such things

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With the complexity of these systems, with the new features that sometimes conflict with other parts of the software, it is not easy to be able to debug everything and try all possible combinations.

The story of having a track that has the tag BPM = 20000 is definitely an unusual and impossible thing to achieve in reality, that is to say that the only way is to use MP3Tag (for example) to write that wrong value. If that track had been fully analyzed by Engine Prime, then that error would have been corrected and there could be no BPM = 20000.

Yeah I’m not expecting the player to actually play back the file with 20000 BPM, but surely Denon’s QA testing should have tested edge cases like this purely for stability and preventing the player from outright rebooting?

Ok, but in this case I would recommend a nice cleanup of all the useless TAGs with the MP3Tag, then a nice analysis of the file with an MP3 verification utility, and finally I would do a grid analysis with Engine Prime. Only after these steps could I be comfortable enough to use that track on the console.

Yes, you are right, this doesn’t have to happen. However, as I have already written, it is not always possible to predict all the possible combinations that can lead to bugs in the firmware.

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Secondo me il problema non e’ sulle tracce scaricate o tag sbagliati…la stessa traccia caricata sul deck mi ha bloccato il sistema…dopo il riavvio la stessa traccia si e’ caricata tranquillamente…secondo me e’ problema di firmware…questo e’ il mio modesto parere…pero Denon si deve dare una mossa a portare soluzioni nuove…e aggiornare anche Engine Prime un software lento in tutto…persino a creare una cartella ci vuole piu’ di 30/50 secondi…diversamente da rekordbox molto piu’ prestazionale in tutto!

In my opinion the problem is not on the downloaded tracks or wrong tags … the same track loaded on the deck blocked my system … after the restart the same track loaded quietly … in my opinion and firmware problem … this is my humble opinion … but Denon must give a move to bring new solutions … and also update Engine Prime a slow software in everything … even to create a folder there takes more than 30/50 seconds … unlike rekordbox much more performance in everything!

There is so many edge cases you can’t plan for. 20000 BPM.

Say for example, they tested 2000 BPM and that was okay. they tried 10000 BPM and that was okay. Maybe 18000 BPM was okay. When do they stop testing combinations?

Another example is if the software rebooted after seeing a six letter "A"s in a row (EG: AAAAAAH.mp3). How would we know that five "A"s was fine?

It’s a tricky balance of testing everything in software/firmware and getting things not crash but when there is a variable added with a number (or letter) then the possible combinations are, well, infinity.

The best thing to do is build crash guards in place to stop the rebooting. If the Prime console saw 20000 as a BPM, what action does it take? Does it refuse to load? Or does it eject the track with a corrupt logo next to it?

Even software that has been out for 10+ years get caught on random characters or edge-case situations. I would like to see something that minimises the state the player gets into when something bad happens. I wouldn’t want to see the whole thing being rebooted as a Prime 4 user, it would kill the mixer. Not good. Definitely worth uploading ANY file that causes the system to break so safeguards are built in by the devs to help stop set-killing occurrences.

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