need help with this version of pkhex

[ilovepokemon321]

ok so ive been using this for yrs know how it works no problem i ALWAYS back up my pk hex saves just in case i do some thing stupid well im on the newest version of pkhex 

my problem is i tried to open my pokemon sun and moon saves from past pk hex but i keep getting the message that the input file is too small so it wont open it what i normally do is open two pk hexs and load one with ultra sun im playing then load the other with pokemon moon then i just drag the pokemon from one game save to the other that way i dont have to trade and dont lose the pokemon from one game and i get to have it in both can any one help me with this error why is the input file TOO SMALL its from the same programme just the updated version 

can i get a little help please thank you    

 

[Kaphotics]

not a problem with pkhex, you need to re-export your save file as the file you are trying to load is invalid.

[ilovepokemon321]

oh ok i went back and had a look for some unknown reason the save i was trying to load had 0KB i dont know why when all the others have 432KB so i deleted those 2 saves and now when i load the others no problem at all i still dont know why it had no KB 

THANKS FOR REPLYING