Toolkit error: A non-compatible unit exists in Database

Title pretty much says it all, - I acquired a job lot of 2nd user Saturn DLT's. I've added a couple of them already with no problem, now I've connected up another on the bench & programmed it up as required. It saves the programming to the physical unit OK, but the option to add it to the database is dimmed out, and an error is shown on the save dialog: "A non-compatible unit exists in Database"

No hint as to what database unit it objects to...

I can live without it being in the database I guess, - I can still program it and use it as normal, but for the sake of completeness, I'd like to have the unit in the database...

Any ideas what this error is caused by? - could it be a firmware version issue on the unit?

NB: I have done a search on the forum for the exact error message, and nothing comes up...

TIA

Paul G.

 

Actually, I think I figured out that there is an address conflict with another unit that was removed from the network, but hasn't yet been removed from the database... - numpty mistake!