[Zubersoft]

So please do me a favor - load one of your songs in MobileSheetsPro that is not loading properly, then check to see if the PDF exists using that SD file manager. If the PDF does not exist, then that's not something that MobileSheetsPro can recover from without a library backup file. I'm not sure what would have caused your files to vanish off the device though - that is very concerning. If you copy all of your PDFs into the storage location folder then use Settings->Other Settings->Fix Broken File Paths, that would repair the library in one shot.

Mike