Here's Why You Should Only Use "Block Slack" as Plan B

Explore managing workplace collaboration tools, focusing on integrating Slack with Google Chat, and how Mio syncs systems to boost productivity.
Dominic Kent
Dominic Kent is a content marketer specializing in unified communications and contact centers.
How to block Slack in the office

Need to block Slack in the office?

Slack now boasts 12 million daily active users (DAU).

As one of the most popular productivity tools in the world, Slack connects everyone, anywhere and at all times.

Slack in an extremely valuable tool to have. After all, constant communication paves the way for collaboration.

If all your employees used Slack alone, you'd have a streamlined digital environment for office-workers and remote team members alike.

The only trouble is, Slack may not be the only app you want to use for collaboration.

You might prefer Cisco Webex Teams to accompany your Cisco phone system, or Microsoft Teams alongside your Office 365 strategy.

When Slack isn't the tool you want your teams to use, how do you stop business conversations in unregulated environments?

Why block Slack?

When implementing Microsoft Teams or Webex, talk of blocking Slack sometimes occurs.

If your employees use Slack without your permission, they're sharing data in an environment that you can't monitor or regulate.

This leads to issues with privacy, security and compliance. It is not Slack that is the issue - but the way it is managed.

What's more, you could end up with siloed teams as certain employees spend more time checking Slack notifications than paying attention to the tools that you would prefer them to use.

For some, the only solution seems to be learning how to block Slack.

Unfortunately, preventing your employees from accessing their preferred resources is easier said, than done and shadow messaging often lives on.

Shadow IT

1 - Block Slack by blacklisting

The easiest way to block Slack is to treat it as another undesirable entity on your firewall.

Just as you would add explicit sites to a blacklist, you can also add Slack, and keywords associated with it to your filtering list.

Employees can no longer load Slack or check their messages.

2 - Block Slack by port blocking

You can even block your employees from accessing anything other than their emails and the company intranet by port blocking.

Port blocking is when an Internet Service Provider (ISP) identifies Internet traffic by the combination of port number and transport protocol and can block that traffic entirely.

The downside of this is that you could accidentally block a tool that's necessary for productivity.

3 - The problem with blocking Slack

The biggest problem with both of these options is that that they only stop your employees from using Slack on their workplace computers or through the business Wi-Fi.

There's nothing to stop your team members from installing and using Slack on their smartphones and accessing via mobile data.

Slack effectively becomes another shadow IT app like WhatsApp or Facebook.

Even if you could figure out how to block Slack in your office without impacting other apps,  you run the risk of upsetting everyone that favors it for team chat.

By limiting choice in the workplace, you could damage both workplace culture and your reputation as an employer.

So, what are the other options?

What to do when blocking Slack doesn't work


Guidelines could be produced for employees who refuse to stop using Slack.

For instance, let them know that they can only use Slack for basic chat between team members, rather than using it to share sensitive company data. However, these are guidelines and can be interpreted differently or ignored.

How to block someone on Slack

If someone’s bothering you on Slack, you may want to stop their messages. 

Unfortunately, Slack doesn’t have a way to block contacts. 

Most companies rely on Chrome and browser extensions for blocking. But there’s no guarantee those extensions will continue to work with each Slack update. 

The easiest option will be to leave the channel the person is in. You can also ask an administrator to remove someone from a channel if they don’t need to be there. 

Leaving a channel won’t prevent someone from private messaging you on Slack. 

Digging deeper, this is more likely a culture problem than a technology problem. Have a chat with the person or your manager about the situation.

How to mute a person or channel on Slack

One option could be to mute the DMs and channels bothering you. Muting a conversation moves the discussion to the bottom of your Slack channel list. The muted channels and DMs appear greyed out. You’ll be able to see how many messages you’ve missed, like a normal channel. 

Message threads will appear in bold if a teammate creates or replies to a Slack thread in a muted conversation. 

To mute a channel on the Desktop version of Slack, open the channel then:

  • Right click on the channel name in the left sidebar
  • Click Mute channel

To mute a channel on mobile:

  • Open the channel
  • Select the channel name at the top
  • Under Settings select Notifications
  • Toggle Mute Channel to ON
  • The process is the same for muting direct messages on mobile

To mute a direct message on desktop, open the DM you want to mute, then:

  • Right click on the person's name in the left sidebar
  • Select Mute Conversation

Can you hide a Slack channel?

If you don’t want to see any messages after muting a channel, you can hide it.

Right click the channel you want to hide and click View channel details. 

Click on Archive channel for everyone.

Benefits of Slack

A better option is to introduce your employees to the benefits of the chat app you want them to use.

Host a working lunch around  how to make the most of your Cisco Webex Teams tool or your Microsoft Teams accounts.

Send your teams a few blogs from the Slack site and other tips on how to maximize productivity using Slack.

Of course, once again, you're hoping that your employees won't go back to Slack the first time that they encounter a hurdle with the alternative app. And humans are creatures of habit.

If your team members decide to continue using Slack - and you’ve discontinued it - then your IT team won't be aware of it and can’t support it.

The best solution to blocking Slack

You can't just give up on creating a secure, productive and well-synced business environment.

Fortunately, with Mio, you don't have to compromise on your collaboration and communication strategy.

Mio lets teams use the tools that they prefer, without creating silos or security issues.

At the same time, the users that you have allocated new Google accounts to get the tool of your choosing.

By linking your Google Chat spaces and Slack channels together, Mio ensures that everyone keeps working together productivity, without placing additional pressure on your IT teams.

With Mio, messages sent from Slack can appear on Google Chat channels and vice versa.

You can even share files from one app to another, without having to switch between tools. Everyone gets to use the tools they like the most!

Stop trying to figure out how to block Slack in the office and the best solution to blocking Slack.

We speak to enterprises going through this same scenario day in day out.

Learn more at

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