crashing on saving - AP 1.6.4

[mfarooqi]

I had created in may be 1.5.2 or something. (the app store version)... that worked great even in my last beta.  But now when ...

1. I open it
2. edit something.. (even create a new layer)
3. save it

 

it crashes showing an error "

Failed to save document: IMG_3693

Save failed because access to the file was lost.
The document must now be closed.

 

Please see the attached screenshot of error and an animated video showing process.