I know this old question, but I struggled with a similar problem and figure, at least add what worked for me ...
Problem
Running npm list -glists all the packages as expected, and then generates a lot of errors, including missing errors, as mentioned above, and at least for me odd and extraneous errors, such as:
extraneous: aws-sign2@0.5.0 /usr/local/lib/node_modules/npm/node_modules/aws-sign2
I tried a bunch of solutions, including npm upgrade, npm pruneas well as the installation of missing packages, which for me were semver:
missing: semver@2 || 3, required by normalize-package-data@1.0.1
, , , 3.3.6 ( node npm:()
, , , node/npm wiz:
npm update -g
v3.3.6 3.5.3 . , --verbose , , . npm list -g :
/usr/local/lib
โโโ npm@3.5.3
โโโ semver@2.3.2
, -, , - - .