# Custom Plugin fails yarn start with addition of package.json in v7.9.3
**URL:** https://discuss.elastic.co/t/custom-plugin-fails-yarn-start-with-addition-of-package-json-in-v7-9-3/271421
**Category:** Kibana
**Created:** [April 27, 2021, 5:09pm UTC](https://discuss.elastic.co/t/custom-plugin-fails-yarn-start-with-addition-of-package-json-in-v7-9-3/271421 "2021-04-27T17:09:05Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@kbujold\_wr](https://discuss.elastic.co/u/kbujold_wr)
#### Post date: [April 27, 2021, 5:09pm UTC](https://discuss.elastic.co/t/custom-plugin-fails-yarn-start-with-addition-of-package-json-in-v7-9-3/271421/1 "2021-04-27T17:09:05Z")
Hi,
I have a custom plugin that I modeled after "node scripts/generate\_plugin". I am trying to add a package.json file so I can build the plugin and the dependencies. But before I even get to the build, I get this error when I do a "yarn kbn bootstrap" followed by "yarn start"
`FATAL Error: Plugin with id "my_plugin" is already registered!`
Does anyone knows what this is about?
Thanks,
Kris
---
### Author:  [@dosant](https://discuss.elastic.co/u/dosant)
#### Post date: [April 28, 2021, 3:11pm UTC](https://discuss.elastic.co/t/custom-plugin-fails-yarn-start-with-addition-of-package-json-in-v7-9-3/271421/2 "2021-04-28T15:11:35Z")
Hi @kbujold_wr, I am not 100% sure that this is an issue you are hitting, but looks like Kibana had some problems with external plugins in 7.9 [[kbn/plugin-helpers] Building Kibana Platform plugins for 7.9 · Issue #82466 · elastic/kibana · GitHub](https://github.com/elastic/kibana/issues/82466)
Could you try a newer version and try the same steps?
Also, is there a chance that you've somehow created multiple plugins with the same id `my_plugin`?
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### Author:  [@kbujold\_wr](https://discuss.elastic.co/u/kbujold_wr)
#### Post date: [May 13, 2021, 2:31pm UTC](https://discuss.elastic.co/t/custom-plugin-fails-yarn-start-with-addition-of-package-json-in-v7-9-3/271421/3 "2021-05-13T14:31:01Z")
We cannot use 7.10. There is only one plugin. If the package.json file is removed then there is no errors but the node\_modules folder is not created which causes kibana not to launch since there are missing dependencies.
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### Author:  [@kbujold\_wr](https://discuss.elastic.co/u/kbujold_wr)
#### Post date: [May 13, 2021, 9:33pm UTC](https://discuss.elastic.co/t/custom-plugin-fails-yarn-start-with-addition-of-package-json-in-v7-9-3/271421/4 "2021-05-13T21:33:48Z")
I have fixed this issues by updating the package.json start under scripts
from "plugin-helpers start" to "node ../../scripts/kibana --dev"
e.g.
```auto
{
"name": "test",
"version": "0.0.1",
"description": "My Plugin",
"scripts": {
"preinstall": "node ../../preinstall_check",
"kbn": "node ../../scripts/kbn",
"es": "node ../../scripts/es",
"lint":"eslint . --ext .js,.ts,.tsx",
"start": "node ../../scripts/kibana --dev",
"test:server": "plugin-helpers test:server",
"test:browser": "plugin-helpers test:browser",
"build": "plugin-helpers build",
"build-graphql-types": "node scripts/generate_types_from_graphql.js"
},
```
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [June 10, 2021, 9:34pm UTC](https://discuss.elastic.co/t/custom-plugin-fails-yarn-start-with-addition-of-package-json-in-v7-9-3/271421/5 "2021-06-10T21:34:31Z")
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