Junk and Spam Folders

Yes. In classic Outlook for Microsoft 365 there are several built‑in ways to significantly cut down what lands in Junk/Spam and to manage what is already there.

1. Use and tune the Junk Email Filter

• The Junk Email Filter is on by default and moves suspected spam to the Junk Email folder instead of blocking delivery.
• To adjust how aggressively it filters:
  1. Go to Home > Block > Junk Email Options.
  2. Choose a higher protection level (for example, from No Automatic Filtering to a stricter level) as described in changing the level of protection.
• A stricter level will move more suspected spam out of the Inbox and into Junk automatically, keeping the Inbox cleaner.

2. Mark legitimate messages as “Not Junk” To prevent important messages from piling up in Junk:
3. Regularly review the Junk Email folder.
4. For any message that is not junk:
   • Drag it back to Inbox (or another folder), or
   • Select Home > Report > Not Junk.

This trains Outlook and reduces the chance that similar messages will be misclassified in the future.

3. Use Safe Senders and Safe Domains (for Outlook on the web) If some senders or domains keep going to Junk, add them to the safe list so their messages bypass Junk filtering:
4. At the top of Outlook on the web, select Settings.
5. Select Mail > Junk email.
6. Under Safe senders and domains, select Add safe sender and enter the email address or domain.
7. Select OK, then Save.

Messages from these addresses/domains will no longer be moved to Junk, which reduces the volume you have to clean up there.

4. Block obvious junk senders For senders that always send spam, add them to the blocked list (in Outlook on the web):

• In Settings > Mail > Junk email, use the Blocked senders and domains list to stop their mail from reaching the Inbox and keep it in Junk or have it handled by service‑side filtering.

5. Use general anti‑spam practices To reduce how much spam reaches the account at all:

• Rely on Outlook’s Junk E‑mail Filter, which automatically evaluates incoming messages and sends those identified as spam to the Junk E‑mail folder.
• Block automatic picture downloads and external content so spammers cannot confirm the address is active. See Block or unblock automatic picture downloads in email messages from the “10 tips” article.
• Avoid responding to suspicious messages or read‑receipt requests, which can confirm the address to spammers.

6. (Advanced/admin) Disable client‑side Junk filtering If server‑side filtering is already strong and the goal is to stop Outlook’s local Junk logic from moving messages at all, an admin can disable client‑side Junk filtering in classic Outlook via registry:

• Registry path:
  • HKEY_CURRENT_USER\SOFTWARE\Policies\Microsoft\office\16.0\outlook\options\mail
• Create or set DWORD: JunkMailClientScanDisabled = 1.

After this change, all junk filtering is done on the service side, which can simplify behavior and reduce unexpected moves into the local Junk folder.

7. Empty the Junk folder regularly To keep the Junk folder itself from growing large:

• In Outlook on the web, select the Junk Email folder and choose Delete all at the top.
• In classic Outlook, right‑click Junk Email and choose Empty Folder.

Combining stricter filtering, safe/blocked lists, good anti‑spam practices, and (optionally) disabling client‑side filtering will drastically reduce both what reaches the Inbox and what accumulates in Junk/Spam.

References:

• Overview of the Junk Email Filter in classic Outlook
• Filter junk email and spam in Outlook
• 10 tips on how to help reduce spam
• Outlook Junk filtering is running but the Junk Email Options settings are removed

Hi, I'm John! I will help you with this.

Are these spam emails showing up in your Inbox, or are they already going into Junk Email?

If they’re landing in your Inbox, here’s something you can do to start blocking them:

• At the top of your Outlook page, select Settings.
• Choose Mail > Junk email.
• Under Blocked senders and domains, select Add blocked sender.
• Enter the email address you want to block. If you want to block an entire domain (for example, everything from @spamdomain.com), you can enter the domain name instead.
• Select OK, then Save.

For more, please see "Filter junk email and spam in Outlook" https://support.microsoft.com/office/filter-junk-email-and-spam-in-outlook-db786e79-54e2-40cc-904f-d89d57b7f41d

You can also change the level of protection in the Junk Email Filter in Outlook: https://support.microsoft.com/office/change-the-level-of-protection-in-the-junk-email-filter-in-outlook-e89c12d8-9d61-4320-8c57-d982c8d52f6b

Also, did this start suddenly today, or has it been happening for a while? A sudden wave like this can sometimes mean your email was exposed somewhere.

Click "Add comment" to let me know.

Regards,

John J.D.