New Horizon Experience. This article describes the New Horizon Experience, which is available now. As of September 28, 2026, New Horizon is the default starting point on a computer or laptop. In the Horizon WebRef mobile apps for Android and iOS, New Horizon is already what you see. If you still have the older layout, choose Switch to New Horizon from the banner or the top-right account menu (or top-left for RTL language users). You can switch back to Legacy Horizon from that menu any time during the transition.
This article is about the Duplicate account detected message Horizon shows when you try to save contact information on Personal Profile that already belongs to another account. It applies to anyone updating their own profile. Organization administrators cannot start a merge for someone else from this flow. The member who hits the conflict must submit the request themselves.
Horizon does not allow the same person to keep multiple user accounts. That is part of the Terms of Service. When two of your accounts collide on the same cell number, email, or name and address, you use Request account merge so support can combine them.
What the message looks like
When Horizon finds a conflict while you save your profile, a window titled Duplicate account detected appears. It explains that the cell number, email, or name and address already belongs to another account. If that other account looks like yours, choose Request account merge. If it belongs to someone else, choose Cancel and change the conflicting information on your profile instead.
The picture below is only an example screenshot from Help Center. It is not a live notice about your account, and the blurred name hint is not someone on your profile. Your real message appears only in Horizon when you hit a real conflict while saving Personal Profile.
On a computer, the same window uses a wider layout. The words and buttons stay the same, and the Help Center example still is not your personal notice.
Why am I seeing this?
Account merge messages appear for one of these reasons:
Duplicate cell phone number. You are trying to use a mobile number already on another account.
Duplicate email address. You are trying to use an email already on another account.
Duplicate name and address. You are trying to save the same name and address already used by another account.
What do I do?
Horizon starts this path when you update and save Personal Profile. If you have never seen a duplicate-account message, you do not need to request a merge, and you are not eligible to merge accounts on your own.
If you do see Duplicate account detected (or a similar conflicting-account message), decide whether the other account is yours:
If that account is also yours, choose Request account merge and finish any follow-up questions Horizon asks (for example, how the two profiles are related). Choose Same person only when both accounts are truly you.
If the other account belongs to someone else (parent, sibling, child, coworker, or any differently named person), do not request a merge. Remove or replace the conflicting phone number or email on your Personal Profile. Merges are only for accounts that belong to the same person.
What is an account merge?
An account merge combines data from two user accounts into one. One of the accounts is removed. Afterward you have one username and password for Horizon and for every organization you belong to under that remaining account.
How long does an account merge take?
Horizon support reviews each request and either completes or rejects it. Most requests finish within a few hours. Allow up to 2 business days. After the merge completes, your access may be limited until you finish a profile update on your next sign-in so the remaining account details are accurate.
Can I use this to share accounts with my kids?
No. Account merging is not for sharing a login with children. Each person needs their own credentials. Merging is only for combining multiple accounts that belong to the same person. For ways parents can stay in touch with a child's schedule, see How can parents stay in touch with a child's schedule?.
Can I keep my two accounts?
If the two accounts belong to different people, each person may keep their own account. If both accounts are the same person, keeping both is not allowed.
Can I choose which account to keep?
No. Horizon chooses which account remains and which one is removed. The older account is usually kept. If you cannot remember the login after the merge, use How to reset your username or password, or choose Forgot your password? on the sign-in page.
Am I eligible to merge accounts?
You are eligible only when both accounts belong to the same person. Accounts for different people cannot be merged.
I am not eligible for an account merge. What do I do?
If you share an email or cell number with another person and a merge is not allowed:
Use a different email and/or a different landline or mobile number that is not already on another account.
Sharing the same email or the same mobile cell number across accounts is not allowed. If you need that contact info, the other person must sign in and remove or replace it on their profile. If they cannot or will not, you must choose a different email or phone number. Landline numbers may be shared across accounts. Mobile cell numbers cannot.
The other account was deleted. Why is this still a problem?
When a membership is deleted from an organization, Horizon still keeps the email and mobile associations for security and compliance for at least 7 years. Deleting the membership does not free that email or cell number for someone else right away. The original account holder still owns those contact details in Horizon's records for that retention period.
If the original person needs to release or change that email or cell number, they must sign back in (reactivate if needed) and update Personal Profile themselves. See also How to activate my user account.
Can I unmerge or reverse a merge?
No. Once accounts are merged, the change is permanent. If two different people were merged by mistake, one person should register a new account and start fresh.
For example, a parent and child who share the same name should not merge. Keep the accounts separate, and make the names distinct when needed (for example, adding Jr. or Sr.). If those accounts were already merged by mistake, creating a new account for one person is the path forward.
If you still see the older layout
On the older legacy layout, the conflict window may use different wording, such as Not Allowed, with Try Again and a green Request Account Merge button. The rule is the same: request a merge only when both accounts are yours. The Help Center pictures above show the New Horizon window and are still only examples, not your personal notice.