Outlook New suddenly added thousands of contact

Question

These are not contacts I've added. I had a couple dozen contacts saved in Outlook. Then, there were thousands of contacts. Most being only an email address, often looking like some spam email address. It looks like Outlook New decided to add every email address that has ever sent me an email as a contact. When I switch back to Classic, only the contacts I want are listed. I didn't change a setting. It just suddenly was like that one day. How do I fix it?

Answer 1

Hi @Bryan Holmes,

 

Thank you for posting your question in the Microsoft Q&A forum.

I understand how confusing it is to suddenly being flooded of “contacts”, especially if they look like random sender addresses. Could you please let me know did you recently connect another account (e.g., Gmail) in New Outlook, or change any mobile phone contact sync settings (iOS/Android Outlook “Save contacts” toggle)?

Classic desktop Outlook typically shows only your Contacts folder by default and hides Other contacts/directory sets, so your view looked clean. New Outlook/OWA surfaces more sources (Directory/Other/Connected), which made it appear as though Outlook “created” thousands, when it’s often surfacing or collecting them.

This issue could happen because of:

1/ Connected accounts/imports:

Adding a Gmail/other account in New Outlook can surface that account’s contact set (and, in some cases, auto‑create “Other contacts” from mail history).

2/ Mobile “Save contacts”:

Outlook mobile can write recipients you interact with to the device address book (and the address book can sync back to Exchange).

3/ Directory versus Contacts view:

In New Outlook’s People app, the Directory (Global Address List) and Other contacts can appear alongside your personal contacts so it looks like “thousands of contacts” even though many are directory entries or auto‑suggested recipients.

4/ Suggested/collected contacts:

Some tenants enable policies that collect recipients you email into an “Other contacts” container so Scheduling/People experiences can find them. Classic Outlook usually hid these, but New Outlook tends to surface them.

 

While we're waiting for your answer to the question above, here are some steps that often help:

Step 1: Export your true contacts (backup)

• Open New Outlook > People (Contacts).
• Choose the folder that contains your real contacts (often Contacts under your mailbox, not Other contacts).
• Choose Export (CSV).

If you don’t see Export in New Outlook, open Outlook on the web (OWA) at outlook.office.com and look for it.

Step 2: Identify the “surge” container

• In People, expand folders: Contacts, Other contacts, any connected account contact folders, and check if the “thousands” live under Other contacts or a connected account.
• Also check Directory (GAL): those are not deletable personal contacts, they’re organization entries.

Step 3: Bulk‑select and remove only the unwanted ones

• In the folder containing the “thousands,” use View > Select all or the checkbox column to select ranges (you can sort by Created or Email only).
• Delete (they go to Recoverable Items/Deleted Items).
• If you accidentally remove some good contacts, you can restore from Deleted Items or your CSV backup.

Step 4: Turn off sources that re‑create contacts

• Outlook mobile (iOS/Android): Open the Outlook app > Settings > select your business account > change the Save Contacts to Off. If you used the Apple/Google contacts app sync, turn that off as well.
• Connected accounts in New Outlook: Settings (gear) > Accounts > remove any secondary account you don’t need or disable its contact sync.
• Suggested/collected contacts (OWA): In Settings > Mail > Compose and reply, turn off options like automatically add new recipients/Add contacts for people I email (availability varies by tenant, if you don’t see it, your admin policy may control it).

Step 5: Clear “autocomplete” (optional, for the spam suggestions)

In Classic Outlook: File > Options > Mail > Empty Auto‑Complete List.

This won’t delete contacts, but it removes cached suggestions that look like spam addresses.

If you don’t find the toggles I mentioned, your admin may control them via policy. In that case, share this thread with your IT admin and ask them to:

• Confirm whether “collected contacts” is enabled for your mailbox.
• Review any mobile/contact‑sync policies.
• Consider hiding Other contacts in address‑book policies, if appropriate.

I hope this information is helpful. Please follow these steps and let me know if it works for you. If not, we can work together to resolve this.   

Thank you for your patience and your understanding. If you have any questions or need further assistance, please feel free to share them in the comments on this post so I can continue to support you.

I look forward to continuing the conversation.

---

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment". 

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Answer 2

It sounds like you are experiencing an issue where Outlook has automatically added many email addresses as contacts, likely due to the behavior of the Suggested Contacts feature. This feature in Outlook adds email addresses to your Suggested Contacts folder when you send or reply to emails from people who are not already in your Contacts folder.

To resolve this issue, you can try the following steps:

1. Check Suggested Contacts: Look for a folder named "Suggested Contacts" in your Outlook. You can manually delete any unwanted contacts from there.
2. Disable Suggested Contacts: If you want to prevent Outlook from adding new contacts automatically in the future, you can disable the Suggested Contacts feature. This can typically be done in the settings under the Contacts section.
3. Review AutoComplete Settings: Ensure that your AutoComplete settings are configured correctly, as they might also contribute to this behavior.

If you switch back to Classic Outlook and only see the contacts you want, it indicates that the new interface might be displaying these additional contacts due to its handling of Suggested Contacts or AutoComplete entries differently than Classic Outlook.

If the problem persists, consider reaching out to Microsoft Support for more tailored assistance regarding your specific Outlook setup.

---

References:

• AutoComplete not working correctly in Outlook 2010
• Inconsistent performance when working with contacts