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First, I am a beginner of ROS.

I installed Ubuntu 20.04 on my desktop and now I installed noetic on it since they are used in my project team.

However, in my another class, they recommended to install mellodic with Ubuntu 18.04

I found there are some differences between Noetic and Mellodic such as the Python version, catkin_make version etc.

So, I tried to install both Noetic and Mellodic in 20.04 but following error was shown in installing tutorial

$ sudo apt install ros-melodic-desktop-full
E: Unable to locate package ros-melodic-desktop-full 

I double checked that I followed the tutorial well.

There were some answers for similar situations but now I'm worried that those solutions might have a negative effect on Melodics.

So, my question is..

  1. Do you recommend installing both Noetic and Melodic in Ubuntu 20.04?

  2. If not, which version do you recommend to install if you had the same situation as me?

  3. If yes, how can I solve the above error?

I'm not sure this is right place to ask this kind of question

Thank you

my gcc version : gcc (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0 my ubuntu bersion : Ubuntu 20.04.4 LTS

Originally posted by Nu99RI on ROS Answers with karma: 3 on 2022-09-29

Post score: 0

Original comments

Comment by gvdhoorn on 2022-09-30:
What does "install" mean here exactly?

Build from source? Install using apt? Something else?

The direct answer would be: Melodic and Noetic cannot be installed next to each other, as there is no single OS for which binary packages are available for both ROS versions (ie: there is no version of Ubuntu for which binary packages of both Melodic and Noetic exist).

Comment by Nu99RI on 2022-10-01:
I meant using apt. Thank you for your replying!


1 Answer 1


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As I wrote in my comment: installing both Melodic and Noetic on the same Debian/Ubuntu OS version is not supported, as there are no binary packages available for those ROS versions which support the same Debian Ubuntu version.

If/when people need to run Melodic on Ubuntu Focal (which only supports Noetic), I've seen Docker or other container approaches (such as Singularity, or LXC) used.

A from-source build could work, but it's not going to be a smooth experience, and is not something I would recommend to someone just starting out with ROS.

Originally posted by gvdhoorn with karma: 86574 on 2022-10-01

This answer was ACCEPTED on the original site

Post score: 1

Original comments

Comment by Nu99RI on 2022-10-01:
maybe Docker can be used. Thanks a lot!


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