See link below on how to fix password not being accepted in Mail.app on Snow Leopard, when one has enabled 2-step verification on your iCloud account (i.e. icloud.com/me.com/mac.com email accounts). Note that you do NOT have to disable 2-step verification here, just get an app-specific password, as explained in the link: https://groups.google.com/forum/#!topic/uk.comp.sys.mac/jjdUxvO6e2M Should (usually!) only be a Snow Leo problem, as Lion onwards recognises normal password without doing this, via Sys Prefs setup. ...Just a problem I couldn't solve for days, nor even the iCloud specialist at 2nd-line support at the stuffing useless Applecare, either!