Q:

How to remove right click format option to a disk icon in the launcher?

How to remove right click "format" option from a disk icon in the launcher as it can 
lead to formatting by mistake.

A:

As far as I know...the Format option is hardcoded in the Unity source. You can try to edit source code to remove the format item.

NOTE: I recommend you to do this in a Virtual Machine or in a Test Machine to see is everything is OK. (In this example I'm running Ubuntu 12.04 with Unity 5.20.0).

1) Make sure you have enable the Source code repository

Open the Ubuntu Software Center.
In the Menu Bar choose Edit -> Software Sources. Click to enable "Source code repository".
Just in case I use the "Main Server" to Download.

Open a Terminal window Ctrl+Alt+T and type:

sudo apt-get update

2) In the Terminal type the following to install the necessary packages.

sudo apt-get install build-essential quilt

3) Install build dependencies.

sudo apt-get build-dep unity

4) Create a folder to download the source code.

mkdir ~/Downloads/src

cd ~/Downloads/src

5) Download the source code & Export variables.

apt-get source unity

export QUILT_PATCHES=debian/patches

export EDITOR=gedit

6) Create the patch and Edit the source code.

cd unity-5.20.0/

quilt new 99_no_format_option.patch

quilt edit plugins/unityshell/src/DeviceLauncherIcon.cpp

Remove the lines... from 171 to 185.

Save the changes.
7) Build the deb packages.

quilt refresh
fakeroot dpkg-buildpackage

8) Install the deb packages.

cd ..

sudo dpkg -i *deb

9) Finally you can logout and Login to see the changes.
Before:

After:

Hope this helps.

