When I start I start System -> Preferences -> Appearance I see that many of the themes don’t have thumbnails and show a question mark icon instead.
As a result, mate-appearance-properties tries to generate the required thumbnails. This activity loads a single CPU core to almost 100% and never completes. Upon closing mate-appearance-properties the window is closed but the process continues to run, indefinitely in the background, occupying almost 100% of a CPU.
If I kill the process then CPU load returns to normal, but the next time mate-appearance-properties is executed a CPU core is fully utilised again.
Regards, Eber.
That is odd. Here's mine:
Is this a fresh install, fully updated?
What versions are you running? In terminal:
inxi -S
inxi -S
System: Host: eber-VPCEG15FL Kernel: 4.8.0-45-generic x86_64 (64 bit)
Desktop: MATE 1.12.1 Distro: Ubuntu 16.04 xenial
I've installed some themes but it was working fine... and something happened a the icons disappeared as the next image:
The DE works fine but , when I start System -> Preferences -> Appearance, this activity loads a single CPU core to almost 100% and never completes
No nothing
sudo apt -f install
[sudo] password for eber:
Reading package lists… Done
Building dependency tree
Reading state information… Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
What could be a easy fix would be to upgrade to MATE 1.16; your on 1.12.1.
1 Like
ok, thank you. I am going to upgrade to MATE 1.16
I will tell you if it works
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And just to be sure (after):
sudo apt full-upgrade
and reboot
It worked, thank you for your support.
Could you tell me if there is a list about themes that I can install without troubles, or what kind of themes,icons so
Excellent 
Ubuntu Mate supports only the themes you have loaded, but there are third party sources to try at your own risk. Here's one..
For anyone who’s still avoiding GTK3/Mate, something like this should solve it:
# launch the program
mate-appearance-properties
# now close the GUI
# and then get PID of the process
pid=`ps -C mate-appearance-properties -o pid=`
# show files in your home directory opened by the process
lsof -p $pid | grep /home/$USER
# if the problematic files aren't in your home directory, show all files
# except libraries
lsof -p $pid | grep -v /usr/lib
# (re)move the suspect files (usually theme config files) and see if it helps
