Finally Bentley should admit that Microstation(especially Open+ products based on Microstation) corrupts DGN files because of bad file handling and not because of some random external issues. There should be automatic backups for files and Undo buffer so we can recover files after surprise program close . MS Office, web browsers already has such option but not Microstation. Disk space is no longer an issue even for larger files we don't open files directly from 1.44MB floppies anymore.