Hi Rich
Sorry for not getting back on this sooner, I take it trying to recover stuff from your old JB7 backup did not work?
So lets go the "External Drive" rout.
You will need a USB SSD, HDD, or Thumb stick large enough to hold the music you want to transfer. (be aware that most large USB Thumb sticks are "fake" so if you purchase one do so from a shop not e-bay/Amazon)
The First thing you need to do is insert the USB drive device into the B2's USB A port and power up. (The B2 may not recognise that a USB device is attached - this is normal - just keep following the instructions).
Then using the front Display and the round knob go through the menus thus - "Main Menu > Settings > Maintenance > Format USB A" - and wait for the format to complete.
You can then remove the USB device from the B2, it is ready to use.
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You now need to load all the music you want on the B2 onto this USB device.
NOTE
The music must be formatted as described here
To achieve this, on your PC or Mac, create a folder called "music" and in it place all your music collection under a new folder for each artist. Then under these artist folders create a folder for each Album/CD for that artist and in these lower level folders place the tracks for that Album/CD - note you can also include a JPEG file containing the image of the cover art along with the music tracks.
The B2 uses this folder naming structure to display its music holdings, it does not use any MP3 tags that may be present withing the music (although it does not mind them being there).
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Once you have built your "music" directory, use your PC or Mac to write this to the USB device (DO NOT allow the PC or Mac to reformat the USB device).
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Plug the USB device into USB C (or A) at eh back of the B2 and power the B2 up.
Then again using the front display and round knob menu system go - "Main menu > USB Functions > Import from C" and wait for this to complete
once complete
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Press and hold in the Play/Stop button on the B2's front until "saving" appears on the display. Wait for the clock to re-appear then power off the B2 and remove the USB device.
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Now power up the B2 and your music should be there ready for you to play.
Enjoy
Fred