I did a quick scan for some audio files that were on my SD card. Recuva didn't find anything, but suggested I do a deep scan. While that was running (it took 13 hours) the dialog says that it had found 5 files which is about the same as I had lost. When I came back to the computer following the scan Recuva told me that because of filters the 5 files were not recovered. Does anyone know what these filters are or what this message means?