Is there some way or tool to fix a dft corrupted file? (I was working with this file, I saved it, I closed it, then I tried to open it and SE could not open the file.)
There is no tool, but if you have a Maintenance agreement, you can submit it to GTAC either directly or through your VAR to possibly get it fixed if it is worth the wait of a few days to do so.
As far as I am concerned, you are able to download Data Recovery and have a try. It is a very useful program. WIth this software, you can restore corrupted files as soon as possible.
@flx I assume you did the basics first? Hard reboot, restart SE and see if it opens.
You could try going to file properties and select the tab "previous versions" and see if there are any previous saved versions.