The files that have been deleted from the application might be stored on your drive even if they are not accessible anymore. Install Recuva and then use the wizard to look for your files. Select the folder and the drive and then wait for the results. For a more accurate search operation, use the Deep Scan. At the end of the scanning procedure, the list with the recoverable files will be shown. Select the files you need to recover to another place other than the original one.