the answer you seek could reside within your question, somehow the word "Demo" is suspect? I ask you this, as I am unclear by your term "hardly". Can we save data in a hardly kind of way? Is this sometimes yes, sometimes no in getting your data saved, or is this some of the file or files but not all or corrupt?
Have you saved data with this program before, and if so, could you access it after the save?
Now pointing you toward the programs FAQ's & help files. but only with the guaranty, if you search here you will find your answer. first check if the demo allows you to save data, see if others have asked about your same issue, then look into data - saving - backing up - restoring & file types. >"<
-Gods Speed Man-
"keeping it real"