I began with updating the firmware to the latest iteration and installing the driver DELL for the RD1000 - that was supposed to take care of some of the burden and installing an utility. No joy, the Dell utility do recognise the drive( but only if executed with eleveted rights), the driver is still Microsoft and an attempt to see if other drivers were installed on the system (so it could be changed) gave no results.
I then tried the freeeject utility. After several seconds, the elevated prompt returned no error message but no joy either, the cartridge is stil there.
In the explorer, the right clic on the driver and the order to eject is met with contempt and a message that the drive is busy and we have to first wait after or terminate all processes that keep it busy. I suspect Veeam BR, given that it is a repository (no, I don't have the content of the drive selected in explorer;that would be enough to keep a drive busy..
For now, it is only the pressing on the button that ejects the cartridge.
Maybe others have other ideas.