It's interesting that this topic just came up. Yesterday, I was struggling with a similar issue because I opened up an old project and some plugins were missing. Rather than ask me where they could be (e.g., like Kdenlive asks for the location of missing assets), it silently ignored it. What makes it interesting is that this was Carla itself that was missing; while it is available elsewhere and opened up in other tracks, it was not available for one track in the location expected by the project or Qtractor. So, two of the same plugin in two locations - one missing and one not - that's probably why qtractor didnt say anything. Fortunately, I did a screen record for a video that showed each of the plugins and settings. Anyhow..., I better get to reviewing and voting on those two tickets!
It's interesting that this topic just came up. Yesterday, I was struggling with a similar issue because I opened up an old project and some plugins were missing. Rather than ask me where they could be (e.g., like Kdenlive asks for the location of missing assets), it silently ignored it. What makes it interesting is that this was Carla itself that was missing; while it is available elsewhere and opened up in other tracks, it was not available for one track in the location expected by the project or Qtractor. So, two of the same plugin in two locations - one missing and one not - that's probably why qtractor didnt say anything. Fortunately, I did a screen record for a video that showed each of the plugins and settings. Anyhow..., I better get to reviewing and voting on those two tickets!