[bug] Upgrade tool stuck at "Migrating templates"

[yairEO]

Running the migration script is stuck for over half an hour on "Migrating templates…"

A lot of files were modified but I am unsure if all the files were scanned or not.

$ npx @tailwindcss/upgrade
≈ tailwindcss v4.1.18

│ ↳ Upgrading from Tailwind CSS `v3.4.19` 

│ Searching for CSS files in the current directory and its subdirectories… 

│ ↳ Linked `.\frontend\tailwind.config.js` to `.\frontend\src\css\tailwind-base.css` 

│ Migrating JavaScript configuration files… 

(node:24000) [MODULE_TYPELESS_PACKAGE_JSON] Warning: Module type of file:///C:/projects/definity/frontend/tailwind.config.js is not specified and it doesn't parse as CommonJS.
Reparsing as ES module because module syntax was detected. This incurs a performance overhead.
To eliminate this warning, add "type": "module" to C:\projects\definity-app\frontend\package.json.
(Use `node --trace-warnings ...` to show where the warning was created)
│ ↳ The configuration file at `.\frontend\tailwind.config.js` could not be automatically migrated to the new 
│   CSS configuration format, so your CSS has been updated to load your existing configuration file. 

│ Migrating stylesheets…

│ ↳ Migrated stylesheet: `.\frontend\src\css\tailwind-base.css` 

│ Updating dependencies… 

│ ↳ Updated package: `tailwindcss` 

│ ↳ Updated package: `prettier-plugin-tailwindcss`

│ Migrating templates…

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🔗 Similar Issues

Possible Duplicates

• v4 upgrader removing the content of all files in my project #18972

Related Issues

• Upgrade to v4 doesn't work: Cannot apply unknown utility class: bg-opacity-50 #18053
• Tailwind v4 Migration Error: Package path ./base is not exported from package /.../node_modules/tailwindcss #18310
• Tailwind compilation takes forever on css files delete / add #18737
• Tailwindcss 4.1.7 is too slow #18101

👤 Suggested Assignees

• nexxai
• alexkiro
• stevebauman
• njoshi22
• ameerhamzanawaz

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[yairEO]

I've stop the script. committed to GIT the files it changed so far. ran the script script again and a ton of new files where changes and now the script has finished successfully

[wongjn]

This happens often when you have large files in the project. When doing the upgrade, consider temporarily moving the files outside the project while the upgrader does its thing.

[yairEO]

My project isn't THAT huge compared to others I've worked on. yes, many hundreds of files, but not a many thousands. If this happens often then the tool should maybe be added some text, which is shown on the step which is assumed for this to happen on, to alert people they should break and, commit, and start again