Hello. After purchase for the operation of high-speed USB flash drives USB 3.1. The musical material that I record through the Rekorbox program. I ran into a problem on CDJ-850 brand players, and in completely different places. The problem is that when I inserted the flash drives for the first time, they read calmly, but when I reinserted them, any player of the cdj-850 brand would hang dead. Moreover, if you insert the same flash drives on the model from cdj-350 to the latest XDJ-1000mk2 or cdj 2000nxs, then everything is read. I searched the answer to this question on the Internet, and it turns out this problem is known, and was discussed on the Pioneer forums, and on Youtube. In particular, one guy wrote that the file% flash_drive%: \ PIONEER \ USBANLZ \ USBMNG.DAT is created on the USB flash drive by deleting which, the player starts reading the USB flash drive again. But this method helps only once. Most likely the problem is at the firmware level of Cdj-850 players. Please tell me when this problem will be fixed by the release of a firmware update for this player model. After all, it was not long ago removed from production, and given the fact that this model was price-quality, then it stands in a huge number of clubs. P.S. if you use usb 3.0 flash drives then everything is fine, but I want to refuse them, since in the latest macbook pro models starting in 2016, there are usb type-c connectors. And in order not to use adapters for recording on flash drives with old connectors that lead to power surges and erasing the entire playlist base in rekordbox, it is more convenient to use flash drives with two type c ports and an old usb. but they are already 3.1. My flash drive model: Samsung USB 3.1 Flash Drive DUO Plus 256GB.