Dear all, I am building a relatively complex project where different libraries share some functions. These libraries, and the functions are in modules, which I would like to leave in different directories (I work right now on an Appled Power PC, and use gcc 4.3.0 20070810 (experimental)). All was fine until I started to strip some modules from one directory because they need to be used also by other libraries. Then #### gcc -O2 -J../SRC_SYS -I../SRC_SYS -c input.0.0.f90 input.0.0.f90:16.64: use io, only: line_length, line_format ! size of the input line 1 Fatal Error: File 'io.mod' opened at (1) is not a GFORTRAN module file ### The same gcc built the module. The module calls another module, but the module is also in the path with -J (taking out the -I doesn't help). If io.f90 is in the same directory, no problem. I have seen some threads about this, but nobody actually answer the question of why it is happening and why can't it be done or what to do. The source compiles under any fortran 90 compiler (I tried all of them, the exception is Lahey which is not ANSI so the problem is on them) and it is perfectly good code that worked for a long time and still does. Thanks a lot, Lorenzo