[Sandro Takke]

Thanks Steven for the answer

I never noticed any problems in the front with the list. Also we had never problems in tha admin. After deleting one, the problems start. The admin list is the standard a..z list so not many members per letter. It started with only the error using letter M (the deleted record was one with letter M). Later the error is always using the manage option.

Surfing via dashboard to a individual member edit page gives no error.