Now I understand, you left 15 GB free space - to later on test another distribution.
I only have one question: what's about swap? The forum and my own experience are showing, that there might be a bug. So, I'm asking:
The System Monitor/ Resources shows, if swap is active; could you please have a look at it and see:
orx bytes ..% of 2 GiB
?0 bytes (0.0 %) of 0 bytes