I install ubuntu 19.10 and 18.04.3  3 times,  I try different partitions ntfs,  ext4 , I choose a different folder but nothing  same error I get the only way to make the bitcoin-core to work is to let  download the block chain to the default directory but that's not what I want.

by 3 days I try many things but nothing , that's why I choose to open a  post here

On Ubuntu Software-Center somebody else left a review with the same  problem (he can't choose a different folder for the block chain)