Mamiya explains the error in the following way:
The back does not think that there is any available space left on Disk Drive, either on the computer on on the Media Card.
This occurs either because:
1. A valid Capture Folder is not specified in the Capture One software.
If Capture One doesn't know where to put a captured file the body will display No DB. To rectify this, simply make sure that the Capture Folder exists and the Capture Software knows where it is.
2. When the back is connected to the computer, it will receive information about free disk space on the computer. When there is approximately 9 images available to be captured to the computer, the Mamiya Display will show Store 9 and this is counted down to 0. When there is no more available space left the display will show Store DB (afterwhich it may display No DB). At the same time the Capture One application will write Disk Full.
In the event you delete information to make room you may need to update the Back.
In order to update the Back, you need to either reconnect the back to the computer or restart Capture One.
If you see this error on the LCD of a Phase One DF while using an IQ digital back, please ensure your Digital Back firmware is up to date in addition to the above concerns.
If you see this error on the LCD display of the H1 or H2 the solution is as follows: Solution is to update the camera body firmware to available version. Also update the firmware in the camera back.
Fujii GX680 "2-shoot error" or no signal to my digital back.