Ask Your Question

ImportError: No module named 'em', Error

asked 2017-03-23 22:59:24 -0500

tomcattiger gravatar image


I create a test package as tutorial using

catkin_create_pkg beginner_tutorials std_msgs rospy roscpp.

When I add a custom message, it comes error

[100%] Built target beginner_tutorials_generate_messages_lisp

Traceback (most recent call last):

File "/opt/ros/kinetic/share/gencpp/cmake/../../../lib/gencpp/", line 41, in <module>

import genmsg.template_tools

File "/opt/ros/kinetic/lib/python2.7/dist-packages/genmsg/", line 39, in <module>

import em

ImportError: No module named 'em'

beginner_tutorials/CMakeFiles/beginner_tutorials_generate_messages_cpp.dir/build.make:62: recipe for target '/home/arnoldx201/catkin_ws/devel/include/beginner_tutorials/Complex.h' failed

make[2]: * [/home/arnoldx201/catkin_ws/devel/include/beginner_tutorials/Complex.h] Error 1 CMakeFiles/Makefile2:1136: recipe for target 'beginner_tutorials/CMakeFiles/beginner_tutorials_generate_messages_cpp.dir/all' failed

make[1]: * [beginner_tutorials/CMakeFiles/beginner_tutorials_generate_messages_cpp.dir/all] Error 2

Makefile:138: recipe for target 'all' failed

make: * [all] Error 2

Invoking "make -j4 -l4" failed

When I use directly python --> import cm, there is no problem.

Has anyone met the same problem before? Thanks

edit retag flag offensive close merge delete


Hattest du eine Lösung für dein Problem gefunden?

Ich stehe momentan vor dem exakt gleichen Problem und komme nicht weiter :(

fettespferd gravatar imagefettespferd ( 2019-01-21 06:49:08 -0500 )edit

1 Answer

Sort by » oldest newest most voted

answered 2017-03-24 00:14:07 -0500

ahendrix gravatar image

Yes, other users have seen this before.

A quick search on this site for the title of your question turns us: , and , all of which describe different causes for this error and possible solutions.

edit flag offensive delete link more


I had this same problem. The first link had the solution that solved it for me. I needed to install the python empy library. "pip install empy" and then "catkin_make" worked. Thanks!

mkelly66 gravatar imagemkelly66 ( 2019-07-22 22:42:02 -0500 )edit

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

Question Tools

1 follower


Asked: 2017-03-23 22:59:24 -0500

Seen: 9,763 times

Last updated: Mar 24 '17