Stellarium claims that it finished downloading all star catalogues. Storage Usage says that stellarium-data is green. I see that catalogues (0-7) are stored in /home/user/.stellarium/stars/default, and I see identical files in /opt/stellarium/share/stellarium/stars/default No symbolic links in sight. Sigh. Why do I have duplicate files, then?.. Conclusion: download the catalogue, but check your RootFS and home space before and after the download, to see where this file is eating the space. Warning: each consecutive catalogue is larger than a previous one.137k, 600k, 4M, 4.1M, 17M, 44M, 152M, 332M I have no problems with RootFS space now. I am using the latest CSSU-Testing, and had not felt any need to uninstall applications - on the opposite, I install new applications, sometimes. Best wishes.