missing files usb after sync

Just that I got it right - you are trying to sync the same USB device from 2 different rekordbox machine with different Playlists or are the 2 rekordbox DBs are the same and in complete sync?

I think when syncing a rekordbox USB with a different PC the previous DB on the USB stick gets replaced with the new one.

Once the new DB might not include all tracks on the USB stick, the tracks might be still on the USB but not part of the rekordbox DB and therefore not visible on the RX.

Have you checked the Folder view to see if the missing tracks are visible there? 

Hi Frank, no it's 2 machines, 2 different usbs, 2 different collections. I'm wondering if it's an outdated OS on my other machine.... I'm going to try copying that playlist onto this machine and see if that works.

so you're saying you got 2 different machines running rekordbox. You Export different Playlists to different USB sticks. 1 machine is exporting all tracks as expected. The other machine doesn't Export all tracks from the Playlist. However the space used on the USB Looks like all tracks are there....

Sounds like the rekordbox DB on one of the Sticks is corrupt.

Have you checked the USB stick on your PC and looked to the 'content' Folder to see if all tracks are in?

What rekordbox Version you are running on both machines and what is your OS? Have you made sure that all tracks are available on the machine you experienced the issue? 

it turns out that the 6 tracks that play are mp3, all the others are wav/aiff

the machine that's not exporting properly is OS X 10.9.1 and both machines running on the latest version of RB

don't think it's the Db as i've tried 2 different sticks with the same results

do the tracks Play in rekordbox correctly?

yes, the tracks play in rekordbox correctly, fully analysed etc, it's just that when the usb is plugged into xdj rx only the mp3 files show

you Need to wait for the Pioneer guys to look at this or open an inquiry for rekordbox to nail it down.

thanks anyway Frank

Turns out the tracks are there under "tracks" but don't show up under artist (apart from MP3). Weird

My recommendation would be to format the USB drive, rename it (something you've never called it before), then try a full export of your playlists.