Help wanted for reporting common issues to Rack plugin developers

As you use and explore Rack modules on the VCV Library, sometimes you encounter behavior, features, or metadata that aren’t quite correct. To help improve the quality of these plugins, consider reporting the following issues to plugin developers.

  • Missing metadata, such as module descriptions, module tags, and URLs. Have you searched for a tag and not found a module that falls in that category? Could the module description be more descriptive about the module does or is emulating? Suggest it to the developer. Manifest reference

  • Incorrect polyphony support: Does a monophonic module not sum polyphonic audio inputs? Does a polyphonic modules not support up to 16 channels? Do some parameters not accept polyphonic signals? See and to learn exactly how polyphony should work in VCV Rack.

  • Bug reports for crashes, audio glitches, and UI issues. If Rack crashes when you interact with a module in some way, send your <Rack user folder>/log.txt to the module’s developer with a description of how to reproduce the crash and the version of your OS, Rack, and the plugin.

If the plugin’s source code is hosted on GitHub, register for a GitHub account and open an issue explaining the above issue(s). If not, use the provided contact information by clicking on the email icon or author’s website on its VCV Library page.

Remember to be constructive when reporting issues by only offering beneficial time-saving information! Many developers, particularly of open-source and freeware plugins, make plugins for fun and are not obligated to fix issues, although they may appreciate your positive suggestions. Premium/commercial plugin developers are obligated to provide a working plugin but may make a judgment not to implement your suggestion.


When filing a report on github, I will sometimes upload a video of the problem or a simple patch that reproduces it. Github won’t let you upload videos, so you have to .zip the file first, but I suggest this as a way to help the developer spot the problem more quickly.

At my day job we use LiceCAP to capture an animated gif of the bug. Maybe they would be easier to upload?

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If you’re having issues with GitHub’s file size and extension limitations, there are other video hosting sites like,,, and that give you a link to post into an issue.

I wouldn’t recommend GIF because file sizes are 10-100x more than other video formats.

To those who are not developers themselves and have been reporting common issues to Rack plugin developers:

what’s your experience? Do you feel like your efforts make sense and mostly led to actual results?

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Absolutely. I’ve lost track of the number of projects I’ve submitted reports to on github. The vast majority of developers are very responsive and appreciative (especially if you know how to generate results from a debugger).


Come on - you are a “semi developer” at least! I can’t even count how many times you’ve reported “this doesn’t build on linux because you are using inconsistent case in this one specific .h file name”

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Are you on a MAC? I like OSX, but the whole “case preserving but not case sensitive” bit… really stupid decision on their side. I don’t know what they were thinking!