When i try to load visual boy advanced data it says not supported when it has worked in the past

i don't no how wiki answers work yet so ill hav to answer to giv u guys some info well i started playing Pokemon fire red usin visual boy advance and i got 7 of eight badges anyway i saved it the turned off my laptop wen i turned it back on i couldn't load it it said unsupported vba save file 0 can any1 help