Are there any exceptional cases in which a person with O negative blood group cannot donate or any case in which compatibility might not be established between O negative an any other blood group?
There are some situations, where, depending on the interpretation of Rh status, an exception could become possible. Rh +/- commonly refers to the D antigen. However, the Rh group has many antigens in it, including C and E. One can become sensitized to these other antigens and develop a hemolytic response to incompatible C or E type.
Dean L. Blood Groups and Red Cell Antigens [Internet]. Bethesda (MD): National Center for Biotechnology Information (US); 2005. Chapter 7, The Rh blood group.
When the donor has some infections in the blood (HBsAg, HIV, HCV, VDRL etc positive)the blood cannot be donated. For otherwise normal donor, there is no such theoretical contraindication. However, it is always good to do a cross match test before blood transfusion, as there is always some possibility of cross reaction.