# Mkc build fail
**URL:** https://forum.makecode.com/t/mkc-build-fail/37700
**Category:** Help
**Created:** [July 1, 2025, 5:54pm UTC](https://forum.makecode.com/t/mkc-build-fail/37700 "2025-07-01T17:54:23Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@UnsignedArduino](https://forum.makecode.com/u/UnsignedArduino)
#### Post date: [July 1, 2025, 5:54pm UTC](https://forum.makecode.com/t/mkc-build-fail/37700/1 "2025-07-01T17:54:23Z")
I’m trying to use [`mkc`](https://github.com/microsoft/pxt-mkc) but whenever I try to build something (even an empty initialized project) I just get an exception:
```auto
(.venv) F:\MakeCode-Arcade-to-App\examples\Racers\Racers source>mkc build -j
using project: F:\MakeCode-Arcade-to-App\examples\Racers\Racers source/pxt.json
Download new webapp
Download https://arcade.makecode.com/
Exception: SyntaxError: Expected ',' or '}' after property value in JSON at position 1542 (line 34 column 14)
at JSON.parse ()
at parseWebConfigAsync (C:\Users\ckyiu\AppData\Roaming\npm\node_modules\makecode\node_modules\makecode-core\built\downloader.js:41:27)
at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
at async Object.downloadAsync (C:\Users\ckyiu\AppData\Roaming\npm\node_modules\makecode\node_modules\makecode-core\built\downloader.js:101:17)
at async Project.loadEditorAsync (C:\Users\ckyiu\AppData\Roaming\npm\node_modules\makecode\node_modules\makecode-core\built\mkc.js:166:27)
at async resolveProject (C:\Users\ckyiu\AppData\Roaming\npm\node_modules\makecode\node_modules\makecode-core\built\commands.js:131:5)
at async buildCommandOnce (C:\Users\ckyiu\AppData\Roaming\npm\node_modules\makecode\node_modules\makecode-core\built\commands.js:161:17)
at async Command.buildCommand (C:\Users\ckyiu\AppData\Roaming\npm\node_modules\makecode\built\cli.js:43:9)
at async Command.parseAsync (C:\Users\ckyiu\AppData\Roaming\npm\node_modules\makecode\node_modules\commander\lib\command.js:923:5)
at async mainCli (C:\Users\ckyiu\AppData\Roaming\npm\node_modules\makecode\built\cli.js:213:5)
Build failed
```
Was wondering if anyone had any idea why this would happen?
---
### Author:  [@richard](https://forum.makecode.com/u/richard)
#### Post date: [July 1, 2025, 5:55pm UTC](https://forum.makecode.com/t/mkc-build-fail/37700/2 "2025-07-01T17:55:35Z")
@UnsignedArduino i think you just need to update (`npm install -g makecode`)
---
### Author:  [@UnsignedArduino](https://forum.makecode.com/u/UnsignedArduino)
#### Post date: [July 1, 2025, 7:48pm UTC](https://forum.makecode.com/t/mkc-build-fail/37700/3 "2025-07-01T19:48:16Z")
Thanks, that worked! That doesn’t make sense at all though because I did `yarn add makecode` like 10 minutes ago and that didn’t work when I was in the project, now after installing with `npm` it worked. Or maybe cause I ran `npx mkc` instead of `mkc`. I have no idea what made it work…
---
### Author:  [@richard](https://forum.makecode.com/u/richard)
#### Post date: [July 1, 2025, 7:54pm UTC](https://forum.makecode.com/t/mkc-build-fail/37700/4 "2025-07-01T19:54:09Z")
@UnsignedArduino our CLI doesn’t pick up the locally installed version, it assumes it’s always globally installed (though maybe it should)