I had the same issue, too.
Yesterday, I succeeded in copying manually old version of /bin/parted_server (package http://packages.ubuntu.com/trusty-updates/amd64/ubiquity) and /lib/x86_64-linux-gnu/libparted.so.0, /lib/x86_64-linux-gnu/libparted.so.0.0.1(package http://packages.ubuntu.com/trusty/libparted0debian1) during installation.
Since that time it has worked.
IMHO the reason for the issue are several changes in libparted.
I had the same issue, too.
Yesterday, I succeeded in copying manually old version of /bin/parted_server (package http:// packages. ubuntu. com/trusty- updates/ amd64/ubiquity) and /lib/x86_ 64-linux- gnu/libparted. so.0, /lib/x86_ 64-linux- gnu/libparted. so.0.0. 1(package http:// packages. ubuntu. com/trusty/ libparted0debia n1) during installation.
Since that time it has worked.
IMHO the reason for the issue are several changes in libparted.