Solutions:

        1. Format the USB flash disk on the computer as FAT32, and empty the hidden files. 

        2. Copy the decompressed upgrade package to the root directory of USB flash disk.

        3. Insert the USB flash disk into the DVR, find the system information, and click upgrade for USB flash disk.

        4. Restart the computer after the upgrade. Then the upgrade is completed.

    Note: power-off during the upgrade process will cause the failure of upgrade. Some computer may need to upgrade LOGO package after the completion of upgrade. It has to upgrade from the lower version to the high version. The upgrade not in sequence is not possible.