[SOLVED] Calling Accounts.createUser() on schema defined for Meteor.users()

I want to setup a schema for the Meteor.users collection, which I’ve done with the given example from Aldeed’s SimpleSchema. The problem I’m having now is calling Accounts.createUser() as this gives me a very vague Meteor 500 Internal Server Error. What am I doing wrong? Am I even supposed to be using Accounts.createUser() if I’m defining my own schema? Eg. should I be handling this myself instead? Or is there some way of getting these two things to work together?

What is the Meteor 500 Internal Server Error you are getting.
Trying setting optional: true for the user schema fields.

Error
details: undefined
error: 500
errorType: "Meteor.Error"
message: "Internal server error [500]"
reason: "Internal server error"
stack: "errorClass@http://localhost:3000/packages/meteor.js?43b7958c1598803e94014f27f5f622b0bddc0aaf:532:24↵_livedata_result@http://localhost:3000/packages/ddp.js?d1840d3ba04c65ffade261f362e26699b7509706:4964:39↵onMessage@http://localhost:3000/packages/ddp.js?d1840d3ba04c65ffade261f362e26699b7509706:3725:28↵http://localhost:3000/packages/ddp.js?d1840d3ba04c65ffade261f362e26699b7509706:2717:19↵forEach@[native code]↵forEach@http://localhost:3000/packages/underscore.js?0a80a8623e1b40b5df5a05582f288ddd586eaa18:156:18↵onmessage@http://localhost:3000/packages/ddp.js?d1840d3ba04c65ffade261f362e26699b7509706:2716:15↵dispatchEvent@http://localhost:3000/packages/ddp.js?d1840d3ba04c65ffade261f362e26699b7509706:156:27↵_dispatchMessage@http://localhost:3000/packages/ddp.js?d1840d3ba04c65ffade261f362e26699b7509706:1141:23↵_didMessage@http://localhost:3000/packages/ddp.js?d1840d3ba04c65ffade261f362e26699b7509706:1199:34↵onmessage@http://localhost:3000/packages/ddp.js?d1840d3ba04c65ffade261f362e26699b7509706:1346:28"
__proto__: Object

Figured this out. In the standard schema defined as an example for Collection2 + Simple Schema for Meteor.users there is a username field:

username: {
    type: String,
    regEx: /^[a-z0-9A-Z_]{3,15}$/
},

That was causing the trouble as by default the Meteor.users collection defines username as part of profile: {}