SPark 4.0 update error

0 info it worked if it ends with ok
1 verbose cli [ '/usr/local/bin/node', '/usr/local/bin/npm', 'run', 'dev' ]
2 info using npm@2.14.7
3 info using node@v4.2.2
4 verbose run-script [ 'predev', 'dev', 'postdev' ]
5 info predev @
6 info dev @
7 verbose unsafe-perm in lifecycle true
8 info @ Failed to exec dev script
9 verbose stack Error: @ dev: `node node_modules/cross-env/bin/cross-env.js NODE_ENV=development node_modules/webpack/bin/webpack.js --progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js`
9 verbose stack Exit status 1
9 verbose stack     at EventEmitter.<anonymous> (/usr/local/lib/node_modules/npm/lib/utils/lifecycle.js:214:16)
9 verbose stack     at emitTwo (events.js:87:13)
9 verbose stack     at EventEmitter.emit (events.js:172:7)
9 verbose stack     at ChildProcess.<anonymous> (/usr/local/lib/node_modules/npm/lib/utils/spawn.js:24:14)
9 verbose stack     at emitTwo (events.js:87:13)
9 verbose stack     at ChildProcess.emit (events.js:172:7)
9 verbose stack     at maybeClose (internal/child_process.js:818:16)
9 verbose stack     at Process.ChildProcess._handle.onexit (internal/child_process.js:211:5)
10 verbose pkgid @
11 verbose cwd /Users/XXXX/Code/####
12 error Darwin 16.4.0
13 error argv "/usr/local/bin/node" "/usr/local/bin/npm" "run" "dev"
14 error node v4.2.2
15 error npm  v2.14.7
16 error code ELIFECYCLE
17 error @ dev: `node node_modules/cross-env/bin/cross-env.js NODE_ENV=development node_modules/webpack/bin/webpack.js --progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js`
17 error Exit status 1
18 error Failed at the @ dev script 'node node_modules/cross-env/bin/cross-env.js NODE_ENV=development node_modules/webpack/bin/webpack.js --progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js'.
18 error This is most likely a problem with the  package,
18 error not with npm itself.
18 error Tell the author that this fails on your system:
18 error     node node_modules/cross-env/bin/cross-env.js NODE_ENV=development node_modules/webpack/bin/webpack.js --progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js
18 error You can get their info via:
18 error     npm owner ls
18 error There is likely additional logging output above.
19 verbose exit [ 1, true ]

I am having the same problem, did you find a solution?

Many thanks.

I've fixed it. It turns out the problem for me was in a <style /> block of one of my Vue files.

I was using <style lang="sass">, so I tried removing the lang attribute from here and everything then compiled successfully.

If that doesn't fix it for you, try running the dev line from the scripts section in the package.json file manually, as that might give you a better idea of exactly where it's falling over.