Cause
When external storage is not inserted into the display unit, or when the CF card cover is open, an error message is displayed and project files cannot be downloaded.
Moreover, because external storage that the display unit does not support is connected, there is a possibility that it cannot be used.
Solution
Verify whether external storage is properly inserted into the display unit, or whether the CF card cover is closed. When an error message is displayed even if the USB storage is properly connected, remove it first and then reconnect it.
Verify the following with regard to external storage to be used.
Whether the optional CF Card (sold separately) is used
Whether SD Cards other than SD and SDHC are used