Hi George, Sorry for the trouble. I think a fresh install is not the only option, but it might be the simplest ;). It seems there were some challenges with using conda to update, including that it sometimes just seems to take forever. I'm not sure what to do about that. I think pip install should work, but you may need to manually blow away some of the installed folders in "python3.7/site-packages", as there can be confusion about where the newly installed packages go based on the installation method (that this, there might be a folder called 'larch' and there might be one called 'xraylarch-0.9.45-py3.7.egg', and similarly for other packages. You could just blow away (a partial list, and maybe not exhaustive, but ones that I know were changed between 0.9.45. and 0.947 and potentially causing confusion), these folders under python3.7/site-packages/ in your installation: larch xraylarch* pyepics* epics pyshortcuts* wxmplot* lmfit* silx* uncertainties* Then a fresh `pip install xraylarch` should work. If you try that and still run into problems, please let me know what you see. --Matt