Official comment
Sorry to hear that, please file an inquiry ticket here and our support team will gather some additional information to assist you in resolving this issue.
@Dirk > Please add this to your discussion on your ticket.
Dear,
After updating to Rekordbox 6, I analyzed my whole collection so they got the new wave forms. After doing so, I connected my USB (rekordbox 5) and I got the notification to synchronize tag and next to analyze waveform data from the collection drop down menu. I was looking where I could do the last, and by looking around I clicked on the name of my thumb drive (in RB6), and it started deleting all my files on the USB, without a cancel button (it does so by approx 120 at the time), I can't cancel it and I was wondering why on earth it would do that?
Can someone please explain me this? Also its kind of annoying that I have to export everything again. Takes some time.
Thanks

Sorry to hear that, please file an inquiry ticket here and our support team will gather some additional information to assist you in resolving this issue.
@Dirk > Please add this to your discussion on your ticket.
Post is closed for comments.
Yes. I also connected my rekordbox 5 test USB-HDD and selected. Rekordbox delete all playlists...
It's Happening to me right now, Pressed sync manager, connected the usb (with tracks from RB5), and chosen the second option (can't remember exactly what was the messagem but pressed NO, something about "sync tag".
Now it's removing all tracks from USB drive.. we'll see..

And is there any solution for this?
Is there anyone who can respond?
I've tried 2 sticks, but now empty!!!!!
Brrrrrrrr