Moving from A to B/C/D problemo

Hi, all was fine but then… Patterns in Bank A (as loaded onto machine when new) play fine, move Pattern to bank B,C etc and I have nothing- program in tracks as per usual, nothing, the track ‘plays’ (i.e. leds move from 1-16) T1,T2 etc blinks in responds to notes, instrument assigned, no illogical LFO/Start/Lengths etc. . Only difference is on the LCD when TRACK+ T1 or T2 etc. pressed it reads ‘OFF’ whereas on a working ‘A’ bank it reads the assigned instrument. Thew tracks are active, not muted.
So my fellow Elektonauts, how do I get the 'OFF" to change?- can’t find anything in the manual and have tried numerous permutation of various keys

Not finding the file management system easy on this device- shame there’s not a more comprehensive Mac/PC interface (moving samples is easy though)