Ubuntu doesn't retain mouse cursor size between reboots

I was facing the same issue, then found a similar entry under /com/canonical/unity/interface/cursor-scale-factor, increased to 1.20 and it worked fine after reboot. Too bad there's no option under Universal Access or something :S

First note that it is necessary that the theme used in Ubuntu allows the size corresponding to the cursor size.

Therefore, do:

gsettings set org.gnome.desktop.interface cursor-size 16

(or other size, 24, 48, as the theme permits)

But only with this command size will be lost when you restart the session or the system, then to become permanent:

cd /usr/share/glib-2.0/schemas

Make a backup copy of the compiled file of the schemes:

sudo mv gschemas.compiled gschemas.compiled-bak

Then change the default value:

sudo gedit org.gnome.desktop.interface.gschema.xml

Locate this block:

￰ ￰ ￰ ￰ ￰ ￰ ￰ ￰ <key name="cursor-size" type="i" >
￰ ￰ ￰ ￰ ￰ ￰ ￰ ￰ ￰ ￰ ￰ ￰ <default>24</default>
￰ ￰ ￰ ￰ ￰ ￰ ￰ ￰ ￰ ￰ ￰ ￰ <summary>Cursor size</summary>
￰ ￰ ￰ ￰ ￰ ￰ ￰ ￰ ￰ ￰ ￰ ￰ <description>Size of the cursor used as cursor theme.</description>
￰￰ ￰ ￰ ￰ ￰ ￰ ￰ ￰ </key>

Change the value above 24 to 16, 48, 96, that's all, do not change anything.

Save and Exit

Make a new compilation of existing schemes:

sudo glib-compile-schemas /usr/share/glib-2.0/schemas/

This should have generated a new file with the name gschemas.compiled within the directory in question.

Restart the session and / or the system.

The mouse cursor should remain in the chosen size.