This seems to be an important bug. I only tested it with qt frontend. Open some document, say text.lyx. Then File -> Save as..., and type /path/text.lyx in the "File name:" box, where path is a directory that does not exist. You will receive a dialog with "Save failed. Rename and try again?". Choose "Yes". Lyx will prompt a dialog with the message "Could not read direcory" with a button "OK", but pressing it will bring it back in an infinite loop. The only way to get rid of it is by killing lyx.
Regards, Jo�o.
