Actually it isn't. Egypt has no such myth. It is a one sided story.<quoted text> You or any one else can not right off the Exodus accounts of Moses and the Israelites from the land of Egypt, i think, there were some truth there, they can not just fabricate such a story.
Remember, this is a story between two existing nations.
And just think of it, how could a people be lost for forty years in a desert that is 150 miles wide. A fast tortoise could cross it in a month.