Yes, that did work. But then there was a linking problem for the library. It could not find -lXISF. But this change fixed that on my system. this line: target_link_libraries(${PROJECT_NAME} indicore Qt5::Core XISF) changed to: target_link_libraries(${PROJECT_NAME} indicore Qt5::Core ${LibXISF_LIBRARIES}) After I made the changes you suggested and changed that other line it built and linked just fine. So did you want to update it with a PR, or should I? Thanks, RobRead More...