The problem occurs:
It may be that the downloaded library vue was not introduced directly when it was created (due to insufficient permissions when installing directly using npm, and running cmd as an administrator)
method one:
After entering cmd as an administrator, switch to the directory where your vue project is located, and then execute install.
Method Two:
1. Delete the node_modules folder first.
2. Then execute the npm install command to reinstall the package.
Method three:
Go directly to C:/Windows/System32/node_modules to find it, copy and paste it directly into your vue project