I think you do not really need MATE from PPA.
I use MATE 1.12.1 from official xenial universe repository for 6 months and it works great.
You may want to start with purging MATE PPA with sudo ppa-purge ppa:ubuntu-mate-dev/xenial-mate
.
I installed MATE with sudo apt-get install ubuntu-mate-desktop^
.
Or more specific:
sudo apt-get install grub2-themes-ubuntu-mate ubuntu-mate-desktop^ ubuntu-mate-artwork ubuntu-mate-default-settings ubuntu-mate-icon-themes ubuntu-mate-wallpapers-complete human-theme
Then I removed some packages which I do not want to use with: sudo apt-get purge synapse software-center ubuntu-mate-welcome account-plugin-flickr account-plugin-google deja-dup deja-dup-backend-cloudfiles deja-dup-backend-gvfs deja-dup-backend-s3 deja-dup-caja snapd synapse tilda zeitgeist libcontent-hub0 python-zeitgeist zeitgeist-core activity-log-manager-control-center zeitgeist-datahub activity-log-manager alacarte metacity account-plugin-facebook snapd-login-service libsnapd-glib1 click click-apparmor gir1.2-click-0.4 libclick-0.4-0 python3-apparmor-click python3-click-package libubuntu-app-launch2 qtdeclarative5-ubuntu-content1 evince evince-common webbrowser-app
and finally sudo apt-get autoremove
After it I removed Unity and GNOME packages manually with aptitude
. Be careful here.
sudo apt install ubuntu-mate-core
as explained in the PPA's webpage https://launchpad.net/~ubuntu-mate-dev/+archive/ubuntu/xenial-mate – Apr 16 '17 at 01:44