You made my day, prkos, thank you very much! I finally found the hidden folder and replaced the corrupt preferences.xml file and now everything runs perfectly. The case is closed, full gratitude to you and sas!

Thanks, sas, I have seen that link before but I get confused by the "/.inkscape/" address - what does the dot before inkscape mean? There is no folder with that name, I have really searched every corner of my Mac. So you may well be right but I do not know how to find my way to the prefere...

I run Inkscape in Mac OS X 10.5.5 and X11 in XQuartz 2.3.1. Every time I start Inkscape I get an error message about my preferences.xml file being "not valid" or "no read permissions" and no new settings will be saved. I have seen a solution on the net but cannot find the file. H...