I am encountering this issue in CE1.9.1.
When a User registers (doesn't matter if its during checkout or from the Create an Account link) the user keeps getting the password mismatch error even though the password is re-entered correctly.
The form validation does not indicate a miss-match, but once a user clicks on Register it returns the mismatch error.
There is no errors in the chrome console...
I found this: https://magento.stackexchange.com/questions/37381/please-make-sure-your-passwords-match-password-error-in-checkout-with-new-re
But I don't believe it is the same error.
I need to fix it soon, any help is greatly appreciated!
We also had this issue with 1 of our webshops. However we used a checkout extension. So im not sure if this applies for the regular standard checkout. Anyway.
The question should be, are u using a checkout extension?
If so, the value inside the model's file of that extension is set at:
$customer->setConfirmation($password);
but should be:
$customer->setPasswordConfirmation($password);
For me this worked, without changing anything in the core. It's just that the extensions should get a small update, or you can do it manually like i did. Just find that line in the files of the model map of your extension.