Seems to be one of MC's unsolved issues here , I was having a few program freezes with PIC24 debug ( probably a super bug i had coded ! ) so I wondered about PK3 firmware it was 1.28.70 , ( used to be 1.34.17 but lost that ! ) MPLABX said latest should be 1.44.26 , but refused to reprogram the tool ... turned to MPLAB 8.92 it could not see the PKFW .jar file , eventually ! found and copied the PICKIT3.jar ( in MPLABX dir )changed the extention to .zip ! extracted the FW files, moved all these to one directory, opened MPLAB 8.92 , and did a manual reprogram of the PK3 from this directory ... success. Thought I would share ..