I created (by accident/dataimport) a SalesLine with the line number 0. This is not what I wanted and there I tried correcting the error.
I tried deleting the sales line in the Sales Order UI. Result: Navision crash.
I tried deleting the sales line in the Object Designer->Table->ID:37->Run, find the line and delete it. Result: Navision crash.
I tried changing the line no in the object designer: Result: "Do you want to rename the record?". Tried both yes and no. Yes: Cannot rename, No: Nothing done.
I am not sure how I can fix this problem. Suggestions? Do I need someone with a developer license to hack that sales line to have a line number different from 0?
At any rate, I don't feel Navision shouldn't crash due to such an error.