No, the download has not failed. When using any VU download device (e.g. a VDO Downloadkey or a Digidown) with the Siemens VDO digital tachograph the message ‘Download Fault 12’ may occasionally be shown on the tachograph display. This does not indicate a problem with the download process or the downloaded data. Instead it is indicating that the tachograph has not stored any data for one or more days within the download period requested, probably because the tachograph power supply was disconnected for those days. Users should allow the download to finish normally and then press the ‘OK’ button on the tachograph to clear the error message.