Locked out exactly how? Are you getting an error message?
If QBDT opens, but does not let you open your Company file, try opening the last Backup. In the bottom part of the No Company File Open box you'll see Open or Restore an existing Company. Click on that and browse to your last Backup.
If QBDT stops stuck on the Company file, then remove or rename the Company File and QBDT should then open on the above No Company File Open box. My recommendation would be to make a copy of the Folder the Company file is in as a full backup. Then in the original folder KEEP all the Sub Folders (especially the Backup), but delete all the individual Files. Then launch QBDT and when you Restore from the backup it will recreate all those files. So if any of them are also corrupt, they will be recreated. If something doesn't work, you still have the copy of the folder with everything so you can reset to where you were.
If you really need to reload, you can log into your QuickBooks/Intuit online account and download from there.
