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RQT ModuleNotFoundError: No module named 'rclpy._rclpy'

asked 2020-12-01 19:41:24 -0500

mjwhite gravatar image

I get the following error when running rqt on MacOs (Mohave)

Traceback (most recent call last):
      File "/Users/ros/ros2_foxy/ros2-osx/bin/rqt", line 33, in <module>
        sys.exit(load_entry_point('rqt-gui==1.0.6', 'console_scripts', 'rqt')())
      File "/Users/ros/ros2_foxy/ros2-osx/lib/python3.8/site-packages/rqt_gui/", line 87, in main
      File "/Users/ros/ros2_foxy/ros2-osx/lib/python3.8/site-packages/rqt_gui/", line 55, in main
        argv = rclpy.utilities.remove_ros_args(args=argv)
      File "/Users/ros/ros2_foxy/ros2-osx/lib/python3.8/site-packages/rclpy/", line 44, in remove_ros_args
        from rclpy.impl.implementation_singleton import rclpy_implementation
      File "/Users/ros/ros2_foxy/ros2-osx/lib/python3.8/site-packages/rclpy/impl/", line 31, in <module>
        rclpy_implementation = _import('._rclpy')
      File "/Users/ros/ros2_foxy/ros2-osx/lib/python3.8/site-packages/rclpy/impl/", line 28, in _import
        return importlib.import_module(name, package='rclpy')
      File "/usr/local/Cellar/python@3.9/3.9.0_3/Frameworks/Python.framework/Versions/3.9/lib/python3.9/importlib/", line 127, in import_module
        return _bootstrap._gcd_import(name[level:], package, level)
    ModuleNotFoundError: No module named 'rclpy._rclpy'
    The C extension '/Users/ros/ros2_foxy/ros2-osx/lib/python3.8/site-packages/rclpy/' isn't present on the system. Please refer to '' for possible solutions

It appears that at some point along the way the python version switches from 3.8 to 3.9

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1 Answer

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answered 2020-12-01 19:47:09 -0500

mjwhite gravatar image

It looks like the python3 version got upgraded after running Homebrew to install another package as seen by:

python3 --version
Python 3.9.0

I removed the symbolic link and pointed it to the previous version

rm /usr/local/bin/python3
ln -s /usr/local/Cellar/python@3.8/3.8.6_1/bin /usr/local/bin/python3

rqt ran sucessfully after that.

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Asked: 2020-12-01 19:41:24 -0500

Seen: 211 times

Last updated: Dec 01 '20