[quote="dirk-thomas, post:16, topic:3398"] Your error is different than what is discussed in this thread. Therefore I suggest in the future create a new thread or a question on answers.ros.org. [/quote] i thought we are posting ros2 issues in ros discourse. And also, as this topic is related to ament build tests which i created earlier so I linked this issue to this thread. [quote="dirk-thomas, post:16, topic:3398"] Regarding the error message: it looks like you are mixing a newer version of rmw_fastrtps_cpp with an older version of rmw. This is not supported. Either stick two both packages from e.g. the latest release or use both packages from the current default branch. [/quote] I did `sudo apt-get remove ros-ardent-*` and also removed my workspace and then downloaded and reinstalled everything back. How do I solve this again? I think old versions Screenshot from 2018-02-02 11-22-19have stayed in. Please help, it has stopped all my development in ros2 now. I have these installed : ![image|690x31](upload://kIgNVlHa4Agkioyzl8wl6L6bm89.png) --- [Visit Topic](https://discourse.ros.org/t/ament-build-test-failed/3398/17) or reply to this email to respond. If you do not want to receive messages from ros-users please use the unsubscribe link below. If you use the one above, you will stop all of ros-users from receiving updates. ______________________________________________________________________________ ros-users mailing list ros-users@lists.ros.org http://lists.ros.org/mailman/listinfo/ros-users Unsubscribe: