I suspect the free TestDisk utility will tell him the file table is corrupted, possibly unsalvageable, but his computer OS will let him reformat and save new data on it at-will as if nothing happened. The files are all there, just can’t be gotten to. The funny thing is, the undelete flags seem to be more reliable than the main file table some times. If he’d manually deleted everything, he could actually just undelete it in TeskDisk. Prior to him reformatting fully, he could also use the two salvaging utilities to pull individual files off the drive, but there’s no point if that stuff’s backed up already. I bet his drive is physically fine. A full chkdsk in Windows would tell him some useful stuff. Repartition utility Dmitriy Primochenko Online - Repartition Bad Drive would also scan the disk and tell him whether any sectors are problematic and need to be skipped, but most SSDs sort of do that automatically when you do a full reformat.
@N.D.M . There literally is nothing on the drive the prime wiped it completely on its own. I did a disk check and it found nothing wrong. But there was absolutely nothing on drive except for a load of zero byte files in database
A corrupt file table is basically like doing a bad quick reformat. If you’d just done an actual quick reformat accidentally, that TestDisk utility could literally find your old file table and just make it the primary one again. It might be completely fouled up, though. Download and run TestDisk, have it first run the normal and then deep advanced search for the file table. If it finds one, check the file list the table points to, if it’s short or blank then your primary table’s corrupt, if it’s your files, then you might be able to either make it the primary again or even do the file table & boot repairs on it. If not, you can also search for a backup file table. There may or may not be one that is also salvageable that you can then make primary table. It’s worth trying all this stuff, though, because it sounds like this is all just a big inconvenience. You don’t need to worry about losing those files, it seems. So you might as well try it all. When it tries to repair the table and boots for the drive, for instance, it can make it worse if it fails, but in this case it doesn’t matter. If you were really worried about the files, you wouldn’t bother repairing the file table & boot section or trying to find the backup table on there, rather you’d image the drive and then try to pull the files from the image without tampering with it.
@Reticuli. Thanks for that. Due to the fact i start in an hour then its a case i feel of binning it and starting again. More time and agro i didnt need. Ill just have to wing it on serato tonight
While it only takes a couple minutes for TestDisk to search for file tables or even look for the table backup on the drive, even if it can repair it, etc, you’re still risking issues with that drive the rest of the night, so just going with Serato isn’t a bad idea.
I have had this same problem with Pioneer, it was one of the main reasons (but not the only reason) I moved to Denon. I have never had anything like this with Denon, but I don’t use an SSD, just a USB pen drive and always make 2 backup copies on other pen drives after the Pioneer incident to ensure if one doesn’t work, I am not stuck. I have seen this happen to other DJs at massive events right before their set with Pioneer equipment as I have let them use my pen drive when theirs has been totalled by the 2000NXS2. I think having a backup copy is a good idea regardless of what brand you are using as this is potentially a problem with any brand or system.
@Dj-alzy how did the gig go? Im sure you had as much fun on serato. Good thing the Prime4 unlocks serato.
I still manage my library in Serato.
My serato library feeds my engine library
If I have a catastrophic engine library corruption, deleting the engine folders and performing a serato sync gets me running in less than 30 mins.
damn that’s hard …
altho’ the idea of that internal ssd is cool…
've chosen for a MicroSd card to do the job
@mufasa horrible night. Well out of practice on serato lol. Got a banging headache from looking at a small screen all night that was further away than normal. But they all enjoyed themselves so i spose all good really.
@N.D.M it could still happen on a micro sd card lol. The joys of being a mobile dj and carrying a big library lmao
it could still happen on a micro sd card lol.
'm limiting the chances of that happening by taking it out of the prime 4 after closing down each time. also when i rework the library i connect the card straight to my pc instead of through connection with the prime 4. i find it most stable for my needs this way. especially for quick reloads
I agree. On paper it sounds like a great idea.
I’ve read posts here about folks installing separate SSD into a pair of 5/6000. I don’t get it. How are you supposed to maintain the library even with one SSD installed.
@Dj-alzy glad the gig was a success. What are you going to do about the ssd? Format and start afresh?
I know it doesn’t help now, but I’ve used Pioneer systems AND Denon and work in IT as a living… I never put my trust in anything that relies on storage. Whether it’s physical hard drives or SSD, they are both vulnable to failure. My main PC has an external USB drive that I store every track I own or download. I then have another identical drive that is created by Denon and/or Pioneer (depending on system Im using). It’s this identical drive that feeds the Denon. If the worst happens and this drive fails or corrupts, I can reformat and rebuild from my original PC drive. However, I also ALWAYS have 2 identical USB pen drives that contain a folder of New tracks and a folder of classic house tracks, just enough to last a 3 or 4 hour set. Should my main drive go AWOL during a gig, I can plug these drives in and work from those, not ideal but at least the gig has music! Bottom line saftly net if my setup seems too long winded… Once your Denon drive is all good and working, GO BUY ANOTHER SPARE DRIVE and clone it, you’ve always got that backup (even if its a couple of months out of date since you last cloned), you can swap it out. Prices of drives won’t break the bank, but at least you have that piece of mind. PLease always backup, I know its tedious, but long term you’ll enjoy the DJing and not stress about losing everything!
Good Day @DJMarkyMarkUK,
thanks for your precious post regarding “back up”. I proceed as well (making independent copies on an USB-Stick / Server).
One short Question: Did you ever test the backup or did you need to restore? Were the “HotCues” , “Loops” and “Playlists” saved as in the production environment?
Some weeks ago, I had to restore some single tracks (not a complete restore), and I was surprised that “HotCues”, “Loops” and “Playlists” had not been restored.
So I posted as follows: https://community.enginedj.com/t/prime-4-restore-db/39113
I regret all guys, who have a data crash and no back up files, and furthermore never tested, if they work properly.
I’m looking forward to hearing of you and thanks in advance.
Brgds
BeatMaster
Doing it via the Prime 4 connection isn’t possible anyway. For some unknown reason the SD card slot doesn’t show as storage when connected to a computer.
@mufasa I had hard drives installed into each of my old HS5500 players. Using the Music Manager software, I had to do everything twice - once on each player.
There was no way of telling the software to treat the drives as clones. That option would still benefit some users today with Engine DJ.
And those could be as reliable in dealing with drives as the Hanpins are, especially if you used the DDJ Music Manager ahead of time, once again because of a lack of constant automatic writes. If you did plug in a drive that had no database, then I believe the 5500s scan and write to the drive just once automatically when you first plug the drive in to build a searchable database, but that’s minor.
We know why these issues occur: frequent automatic writes to these drives that cannot be disabled with Engine OS. We know how to easily fix this, and we know read-only is viable because streaming services on Prime gear are able to work without writes to drives. Allowing such options would produce certainty in results while not preventing users from permitting writes, especially if they have backups.
I don’t understand you !! you spent 2200 euros for the prime 4 and 100 euros for an internal ssd !! you are afraid to spend another 100 euros for a usb c ssd where you have the same backup of the library, after all it takes 5 more minutes to synchronize both the library of the prime 4 and that of the external backup ssd ! come here to write i go back to pioneer! instead of trying to prevent the problem with a backup !! then what can I say that I was 300 km from home and my macbook ssd broke and or had to use my iphone to complete the evening !! now with denon and a backup on the external ssd are in place !! any pc could lose the files but you are able to blame only denon !!
Thats part of the issue i wasnt actually at home with all my backups… How many bsckups do i need to carry… cant find tbat bit in manual . So i have now decided to do it a different way. Folders on hard drive are now crates are now playlists. I.e. put all tracks into there own playlist folder crate. Then drag those to collection. If it decides to do it again then I’m in controll as all tracks are withing a hard folder on drive that is NOT created by denon. And the primes will still read the folders as per. See denon thats how simple it can be… now im off to try and complicate the ■■■■ out of the system. Im now going to call my folders bins.and playlists are now request sheets. Crates are now boxes.
This is how it should be done 
. I have never dumped all my tracks in 1 folder and then relied on any software to organise them. Fk that for a game of laughs.
Keep tracks well organised and tagged on a drive your way, when you make a new folder drag that into Engine just for a fast analysis run.
This way no one will ever get stressed over playlists being forever lost or need away to migrate from one software playlist to another (unless you demand hotcues!)
Keep and maintain a folder system on a drive but always make a full backup as digital files can become corrupt or a drive fail without notice.
On a note - just take what you need for the event or night on a backup drive for that “just in case”. You won’t need your entire library!
Yeah i used to do it this way. Then in my own stupidity i decided to use that useless "sync " button in prime. Lesson learnt the hard way… do it the good old fashioned way…
“Folders on hard drive are now crates are now playlists. I.e. put all tracks into there own playlist folder crate. Then drag those to collection. If it decides to do it again then I’m in control ”
Could you please explain the method real slow for a confused Denon-novice? I am in the process of sorting my very big library into “real folders” on my main disk, sorted into genres: (Reggae Example: folders called “Dub”, “Lovers Rock”, “Hits”, “British reggae” and so on). I also have folders for house, electro, ambient, jazz, soul, Afro, filmscores, evergreens…and folders containing artists (James Brown folder = 7 albums / Portishead folder = 3 albums)
I haven’t started Engine yet, and haven’t tried to sync…am afraid to go down the wrong road.
I like to now exactly where the physical files belong - in which folders. It matches my brain and memory. And, I’m really aware of system failure. I want to be able to restore a playlist fast if I get in similar problems like you…I play better sets when everything is accounted for.
How do I create playlists/sync if I wanna make selections from different physical folders? ( example: a playlist with tracks from very different folders. Motown soul → ska → early Marley → dub → electro - breakdance )
Am I doing it wrong?
I’m using a Prime 2 with internal Samsung SSD + backups for every gig/playlist on SD cards.
Advice are welcome 
Thanks