Hi! We are using MCC17 2.20 with the fancy linker and assembler. I just added a new source code module and for some reason when the program links it gives me the error message which is the subject line of this message. The problem is that this variable worked fine (tested it) before the new module was added to the project. For example the file with main() in it defines the variable as follows: #pragma romdata ourdata rom unsigned char MessReadyFlag1, BackSlash1; And the file that uses the external declaration of the MessReadyFlag1 defines it as follows: #pragma romdata ourdata extern rom unsigned char MessReadyFlag1, BackSlash1; The new source code interferes with the old code even when its data is "#pragma'd" into another section. We thought that we had overcome all of the linker issues/problems (via self learning). However this problem baffles us. If you have any comments about what may be happening, then please drop me a line. thanks Chris Eh? Chris Adamson, Programmer Identec Solutions cadamson@identec.com phone: 1-250-860-6567