THANK YOU everyone for your help with this situation.. The file was indeed GONE.. none of the tools worked, and... the file simply wasn't there.. Bottom line, if you have a VERY large media file (over 3.5GB):
1. DO NOT MANAGE/MANIPULATE movement of that file using 3rd part image viewing tools
2. If you do, use COPY function instead of MOVE. confirm file is where it needs to be, then delete from original location.
3. if possible use file manager tools like MYYFILES, Total Commander, etc. to move/copy files around not tools like QuckPic, Gallery, etc.
I've now re-created this issue tens of times and YES, its real. A file size of greater than 3.5GB, when MOVED (using 3rd part tools), will will simply DISAPPEAR (the file and the allocated space).
Again, thank you.. ADMINS, you can consider this matter closed.