Unable To Update Profile: Error The Username Or Email You Have Chosen Already Exists. Please Try Another One

None of my customer's can update their own profile information.

When they access their edit profile link: https://mysite.com/profiles-update/?selected_section=general

After they click on save they get the error:

Error The username or email you have chosen already exists. Please try another one.

This error makes sense if they were adding a new account to prevent duplicate email addresses, but they are editing their information.

Any clues on how to allow them to save their edited information?

I also get this message :

The username or email you have chosen already exists. You cannot checkout as guest if you already have an account with this email. Please try to login or recover your password. Please contact us with any questions.

Worst than you, my customers can't even checkout. I'll open a ticket and will report back.

I figured it out. It was due to duplicate customers (same email one active and the other disabled). I removed all duplicates.

Now I always get "The profile data has been updated successfully." every time a user checks out. but it's better than an error!