Rekordbox DJ (DDJ RB) problems - sort order, tracks vanishing etc

(ARRGH Just typed all this in and the browser locked up!)

Hi. I have just picked up a DDJ RB. Have a few problems with Rekordbox DJ.

Problem 1: 

Sometimes the tracks aren’t sorted in the correct order. For example, if I sort by Artist Name, it should be sorted like this:

 AAA Artist – Track 1

AAA Artist – Track 2

AAA Artist – Track 3

BBB Artist – Track 1

BBB Artist – Track 2

CC Artist – Track 1

CCC Artist – Track 2 

However, sometimes it sorts along these lines, seemingly by Artist Name, but with some random placements: 

AAA Artist – Track 1

AAA Artist – Track 2

BBB Artist – Track 1

BBB Artist – Track 2

AAA Artist – Track 3

CCC Artist – Track 1

CCC Artist – Track 2

Problem 2:

Sometimes a track will disappear from the browser when I drag it onto a deck. The track doesn’t load onto the deck (I get a message along the lines of “Track not loaded”) and then it’s not visible in the Rekordbox browser any more. Switching folders backwards and forwards a few times brings it back. This is NOT a problem with any particular MP3 as these tracks do load on second time of trying.

Similar problem: 

Same as above, apart from the track is still visible in the browser – it just doesn’t load first time. 

Sometimes I get a combination of all three problems, which is fun!

Running last RB DJ, latest DDJ RB firmware + drivers, Win 10, 8GB RAM, all music stored on external USB 3 HDD.