Cannot Open Design

[ngancekale]

Hi
I was trying to open one of my house designs and it says the file is already opened but I cannot see it. I can see the other house designs but not the one I am after even though it says it is already opened when I try to open it again, I closed the Sweet Home 3d software and re-opened it but still the same. I also restart my computer but it is still the same.

THis problem started just today after. The file that I am trying to open but cannot open is 18MB. The other files are smaller in sige and they can easily open.

Please help open my design as I have put lot of efforts into it, and one which I consider my master piece.

Thanks
George, Jiwaka, PNG