When I try npm install new packages it shows me this error:
<rollbackFailedOptional: verb npm-session 585aaecfe5f9a82
If you have access to the registry but the error is still occurred nothing mentioned above wouldn't work. I noted that this problem is only applicable for local project's installation (i.e. if you use -g to global install everything is working fine).
What's resolved the problem for me: just remove an entry regarding a package you're going to install from a project's package.json file. After that next call to npm will work and install the package successfully.