I have gone through all the similar questions asked about this problem and tried the workarounds mentioned over there but nothing works. Like the " ps | grep 'dmsetup create' " workaround simply doesn't work, because I don't get any output displaying any PID (so I can't kill any process), then the one regarding deleting 30_os-prober just deletes the file but has no effect on the installation. I am trying to do a clean install on a HDD, can anyone please help me solve this problem. [I am installing Ubuntu LTS 20.04.1 from a live USB]
UPDATE: Problem solved! Instead of choosing the option "Erase disk and Install" I chose "Something Else" and proceeded with a Minimal Installation. Prior to this, I just booted from the live USB and opened GParted, and then manually deleted all the partitions and created a new msdos partition. And then in that "Something Else" option I just chose the newly created partition for the installation.