I am working on a site grading plan. I have 15-20 alignments, a corridor, some grading feature lines and 3 surfaces (existing, datum and top). I have found at least one alignment that I THINK is causing a problem. CAD begin running strange and then began "closing unexpectedly". I have disassociated that alignment with everything in the drawing, but when I try to delete, erase or modify it, the program shuts down. I tried to "copy and paste" my corridor into a new drawing (which would leave behind the corrupt alignment) but that, too, causes the program to close. Help. Too late to start over on the entire plan (which is what I will have to do if I can't get rid of this alignment). It is causing problems with other commands also.