Microsoft finally released the SharePoint Framework version 1.12, nine months after the release of version 1.11, but pretty soon was known that the latest version had several and severe issues. After just a couple of weeks, Microsoft deprecated and made unavailable version 1.12, and recommends going back to version 1.11 till version 1.12.1 will be offered.

Normally, when a new SharePoint Framework is released, an updated version of the SharePoint Framework Yeoman generator is also announced to support the new functionality of the Framework. Because of the problems with version 1.12, you should be back as well to the 1.11 version of the Yeoman generator.

To check for outdated npm packages (in general), use the next command. The packages relevant for SharePoint Framework will begin with @microsoft/sp-

npm outdated

If you installed by accident version 1.12 of the SharePoint Framework version, you could remove it from your project using the command:

npm uninstall @microsoft/{spfx-package-name}@1.12

And to install back version 1.11, use the command:

npm install @microsoft/{spfx-package-name}@1.11 --save --save-exact

Updating the package updates the version number in the package.json file and the lock file used in your project. After the new package is installed, clean up any old build artifacts using the command:

gulp clean

To be sure that everything will work correctly avoiding any conflict with old versions, it is recommended to delete all old packages by deleting the node_modules folder and download and reinstall all the dependencies using the command:

npm install

To see outdated versions of the Yeoman generator, run the following script and look for the items with the prefix generator-sharepoint

npm outdated -g

To see which generator version is installed, use the next command. Normally, as early said, the version of the generator is also the SharePoint Framework installed.

npm ls -g --depth=0

To uninstall the Yeoman generator, use the command:

npm uninstall -g @microsoft/sharepoint@1.12

And to install version 1.11 of the Yeoman generator, use the command:

npm install -g @microsoft/generator-sharepoint@1.11