Every morning, it's the same ritual for many small business employees in Quebec: opening Outlook and sorting through a dozen emails that have no business being in the inbox. Dubious promotions, fake invoices, unsolicited newsletters. These spam emails waste time, but more importantly, they often serve as gateways for phishing and ransomware attacks.
The good news is that Outlook offers several tools to regain control of your inbox. This guide shows you how to block spam and unwanted senders on the desktop, web, and mobile app, and when it's best to switch to managed protection for your business.
Quick answer: To block spam in Outlook, right-click the message, choose Junk Email, and then Block Sender. You can also adjust the filtering level in the Junk Email options and block an entire domain. On Outlook web and mobile, the Block option is located in the message menu.
1. Why spam is costing your SME dearly
Spam isn't just a nuisance. It's a real risk to your business's security. The vast majority of cyberattacks targeting small businesses begin with an email: a fake delivery notification, a bogus payment request, a link leading to a malicious page. A single click from a rushed employee can be enough to compromise an entire network.
Beyond the danger, there's the hidden cost of wasted time. If each member of your team spends ten minutes a day sorting through spam emails, that represents hours of lost productivity every week. For a small business in Trois-Rivières or the Mauricie region with a small team, that's far from negligible.
- Risk of phishing and identity theft
- Daily time wasted for the entire team
- Inbox full, real messages drowned out by the noise
- A common entry point for ransomware
2. Block a specific sender in Outlook
The fastest way to block spam from a known source is to block the sender directly. In the Outlook application on Windows, this takes only a few seconds.
- Right-click on the unwanted email in your message list.
- In the menu, hover over Junk Mail.
- Click on Block sender.
The message is immediately sent to the Junk Email folder, and all future emails from that address will be automatically directed there. You can view and manage your blocked senders list at any time in your Junk Email settings, which is handy if you accidentally block an address and want to remove it.
3. Adjust the spam filtering level
Outlook allows you to adjust the aggressiveness of its filter. Depending on the volume of spam you receive, you can choose a stricter or more lenient level.
Open the Home, click Junk Email, and then Junk Email Options. There you'll find several protection levels, from the most permissive to the most restrictive. A higher level catches more spam, but keep a close eye on your junk folder for the first few days, as legitimate messages may end up there by mistake.
- No automatic filtering : only blocked senders are excluded.
- Weak : catches the most obvious spam.
- High : strict filtering, to be closely monitored.
- Approved lists only : only your trusted contacts arrive in the inbox.
For businesses that want a structured approach to email security, our managed IT services include the configuration of advanced filters far beyond what Outlook offers by default.
4. Block an entire domain
Sometimes the problem doesn't originate from a single address, but from an entire domain. If you're receiving spam from multiple addresses ending with the same domain name, you can block the entire domain rather than each address individually.
In Junk Email Options, go to the Blocked Senders, click Add, and then enter the full domain. All emails from this domain will now be treated as junk. This is very effective against waves of spam that constantly change their address but keep the same sending domain.
- Useful against the massive spamming of the same service.
- Avoid blocking dozens of individual addresses.
- Use with caution so as not to block a legitimate partner.
5. Block spam on Outlook web and mobile
Do you often work in your browser or on your phone? The same tools are available, just barely updated.
On Outlook web
Open the email, click the three dots in the top right corner of the message, select Block, and then confirm. The message is moved and the sender is added to your block list. You can manage this list in your settings, under Mail and then Junk Email.
On the mobile app
In the Outlook app on iOS or Android, open the message, tap the three dots, and then select the option to move it to junk mail or report it. Reporting also helps Microsoft improve its filters for everyone.
6. When manual locking is no longer sufficient
Blocking spam manually works well for personal use. But for a business, it's a never-ending battle: spammers change their addresses, spoof legitimate senders, and disguise their attacks as credible internal messages. At this point, Outlook's built-in filter quickly shows its limitations.
Managed protection works upstream, even before the email reaches the inbox. It analyzes links, verifies the sender's authenticity, quarantines suspicious attachments, and applies security rules across the entire organization. This is the kind of protection that SMEs in Trois-Rivières and the Mauricie region are adopting for peace of mind.
- Advanced filtering before email delivery.
- Protection against identity theft and targeted phishing.
- Uniform rules for all employees, without individual configuration.
- Continuous monitoring and adjustment by specialists.
Frequently Asked Questions
How do I unblock a sender who was accidentally blocked in Outlook?
Go to your Junk Email Options, open the Blocked Senders tab, select the address in question, and click Remove. The sender will then be able to email you normally again.
Does blocking a sender really delete their emails?
Not quite. The messages don't disappear: they're redirected to your Junk Email folder instead of your Inbox. You can empty this folder regularly or configure it to empty automatically.
Why am I still receiving spam despite the block?
Because spammers are constantly changing their addresses and domains, manual blocking can't keep up. A managed email security solution filters threats based on their behavior, not just their address, which is far more effective in the long run.
Protect your SME's email in Mauricie
Blocking spam in Outlook is a good first step, but true peace of mind requires a comprehensive security strategy. Our team helps businesses in Trois-Rivières and throughout the Mauricie region implement robust email protection tailored to their specific needs. Discover our IT services for SMEs or contact us directly through our contact to discuss your requirements.