Comment 6 for bug 1874522

I'm having the same problem replacing 18.04 with 20.4, in my case it crashed saying that the disk is currently in use followed by

>Ubiquity: AssertionError: Failed to mount the target: /target

I also have a video of the failed installation flow, I reproduced the problem several times but not the last few times I tried, maybe there is some detail in the flow I'm missing. Let me know if any other info is needed.