Jo,
An almost identical question was asked yesterday. Here is my response.
Instead of simply "deleting" the subproject, it first needs to be
unlinked from the master. To do that, select the summary line
representing the insertion point of the subproject in the master and hit
the Task Information icon (or Project/Task Information) and select the
Advanced tab. Uncheck the "Link to project" box and hit "OK". Then do
"Save As" on both the master and the subproject. Now delete the
subproject.
Hope this helps.
John
