problems with full memory

Hello!

I have the free Recuva and when i trying to recover a portable HDD (466GB) who i accidently formated it works fine to recover and move the recoverd files to and other HDD. But i can only recover the files if i stop the scan at 77%. 77% and up to 100% it stands that there is no memory left at the portable drive i trying to recover and that the scan was a failre.

Do anyone knows how to do so i can recover the whole 100%?

Thx in andvace:)