I was in the process for upgrading from version 10 to 12. Since it took some time I went away and returned after a few minutes and found that the system had rebooted. (I am not aware of electricity failure or something similar).
From that I cannot recover. I am stuck with 10 but cannot continue upgrade to 12. I read and tried almost all threads an all forums I could find but nothing helps. I cannot fix/remove the broken dependencies in order to update. The main hit package is python. Each package is stuck requesting with a different version.
I have some data and applications on my system that will be difficult to make from scratch. So erasing the system and doing a clean install is not a good option for me.
How I can remove the broken packages and restore a system to a stable version either 10 or 12?