这是怎么回事？
C:\Users\username>npm install express -g
npm ERR! code EPERM
npm ERR! syscall mkdir
npm ERR! path C:\Download\nodejs\node_cache_cacache
npm ERR! errno EPERM
npm ERR! FetchError: Invalid response body while trying to fetch https://registry.npmjs.org/express: EPERM: operation not permitted, mkdir 'C:\Download\nodejs\node_cache_cacache'
npm ERR! at C:\Download\nodejs\node_modules\npm\node_modules\minipass-fetch\lib\body.js:162:15
npm ERR! at async Arborist.[nodeFromEdge] (C:\Download\nodejs\node_modules\npm\node_modules@npmcli\arborist\lib\arborist\build-ideal-tree.js:1082:19)
npm ERR! at async Arborist.[buildDepStep] (C:\Download\nodejs\node_modules\npm\node_modules@npmcli\arborist\lib\arborist\build-ideal-tree.js:951:11)
npm ERR! at async Arborist.buildIdealTree (C:\Download\nodejs\node_modules\npm\node_modules@npmcli\arborist\lib\arborist\build-ideal-tree.js:215:7)
npm ERR! at async Arborist.reify (C:\Download\nodejs\node_modules\npm\node_modules@npmcli\arborist\lib\arborist\reify.js:152:5)
npm ERR! at async Install.exec (C:\Download\nodejs\node_modules\npm\lib\commands\install.js:157:5)
npm ERR! at async module.exports (C:\Download\nodejs\node_modules\npm\lib\cli.js:66:5)
npm ERR! FetchError: Invalid response body while trying to fetch https://registry.npmjs.org/express: EPERM: operation not permitted, mkdir 'C:\Download\nodejs\node_cache_cacache'
npm ERR! at C:\Download\nodejs\node_modules\npm\node_modules\minipass-fetch\lib\body.js:162:15
npm ERR! at async Arborist.[nodeFromEdge] (C:\Download\nodejs\node_modules\npm\node_modules@npmcli\arborist\lib\arborist\build-ideal-tree.js:1082:19)
npm ERR! at async Arborist.[buildDepStep] (C:\Download\nodejs\node_modules\npm\node_modules@npmcli\arborist\lib\arborist\build-ideal-tree.js:951:11)
npm ERR! at async Arborist.buildIdealTree (C:\Download\nodejs\node_modules\npm\node_modules@npmcli\arborist\lib\arborist\build-ideal-tree.js:215:7)
npm ERR! at async Arborist.reify (C:\Download\nodejs\node_modules\npm\node_modules@npmcli\arborist\lib\arborist\reify.js:152:5)
npm ERR! at async Install.exec (C:\Download\nodejs\node_modules\npm\lib\commands\install.js:157:5)
npm ERR! at async module.exports (C:\Download\nodejs\node_modules\npm\lib\cli.js:66:5) {
npm ERR! code: 'EPERM',
npm ERR! errno: 'EPERM',
npm ERR! syscall: 'mkdir',
npm ERR! path: 'C:\Download\nodejs\node_cache\_cacache',
npm ERR! type: 'system',
npm ERR! requiredBy: '.'
npm ERR! }
npm ERR!
npm ERR! The operation was rejected by your operating system.
npm ERR! It's possible that the file was already in use (by a text editor or antivirus),
npm ERR! or that you lack permissions to access it.
npm ERR!
npm ERR! If you believe this might be a permissions issue, please double-check the
npm ERR! permissions of the file and its containing directories, or try running
npm ERR! the command again as root/Administrator.
npm ERR! A complete log of this run can be found in:
