Office 365 Hanging on Mac When Replying: Easy Fixes

Office 365 Hanging on Mac When Replying? Learn why Outlook freezes and discover easy fixes to stop the spinning beach ball fast.

The first time I experienced Office 365 hanging on Mac when replying, I genuinely thought my MacBook was about to give up on me. The fans kicked in, the cursor turned into the spinning beach ball, and Outlook locked up the second I typed my reply. New emails worked fine. Browsing was smooth. But replying? Completely broken. I immediately checked for the Latest Updates for Office 365, hoping a patch or fix would resolve the issue.

If you are reading this, chances are you have lived through the same confusing moment. And that confusion is exactly what makes office 365 hanging on mac when replying so frustrating.

Why This Issue Feels So Strange

What makes office 365 hanging on mac when replying different from normal crashes is its precision. Everything else works. Only replies freeze. That inconsistency causes people to blame:

Their Mac’s hardware
Their internet connection
Recent macOS updates
Or even user error

I blamed all of the above before realizing the real problem sits inside Outlook itself.

Why Office 365 Freezes Only When Replying on Mac

Replying to an email is not the same as writing a new one. Outlook behaves very differently in reply mode.

When office 365 hanging on mac when replying occurs, Outlook is forced to:

Re-render the entire email thread
Interpret HTML formatting
Load embedded images and tracking pixels
Handle emojis, fonts, and tables
Reapply signatures

This extra workload pushes Outlook’s rendering engine into unstable territory.

I noticed this clearly when replying to marketing emails froze Outlook instantly, while replying to a simple internal email worked without any delay.

The Outlook Rendering Engine Problem

Outlook for Mac relies on a WebKit-based rendering engine. When replying, that engine tries to process every design element from the original message.

Think of it like trying to edit a document filled with invisible formatting marks. Every keystroke forces Outlook to recalculate layout and styling. If anything in that content is malformed, Outlook can enter a loop and appear frozen.

This is one of the most common technical reasons behind office 365 hanging on mac when replying.

The “New Outlook” Editor Bug

One of the least discussed but most impactful causes is a known issue in the New Outlook editor.

Common signs include:

Freeze occurs after typing the first character
Multiple “Outlook Web Content” processes spike CPU usage
New emails still work normally
App does not crash, just becomes unresponsive

In my case, switching back to Legacy Outlook immediately reduced freezes. That moment made it clear this was not a Mac problem. It was an editor problem.

Email Content That Triggers the Freeze

Another overlooked factor is the type of email you reply to.

Emails most likely to trigger office 365 hanging on mac when replying include:

HTML-heavy newsletters
Emails with embedded images
Messages copied from web pages
Corporate emails with complex signatures
Messages containing emojis or unusual fonts

Outlook tries to preserve formatting during replies, and that is often where rendering breaks down.

Profile and Database Corruption Over Time

For users who experience office 365 hanging on mac when replying frequently, local data corruption is often involved.

Outlook stores large local databases. Over time, this can lead to:

Inconsistent cache states
Indexing issues
Writing errors during reply actions

Important insight:

Reinstalling Outlook alone often does not fix this
Creating a new Outlook profile frequently does

I avoided creating a new profile for weeks. Once I finally did it, the freezing stopped almost instantly.

Why Restarting Sometimes Helps (But Doesn’t Fix It)

Some users notice office 365 hanging on mac when replying only after a fresh reboot.

This happens because:

Outlook initializes UI components on first launch
Caching or rendering failures occur early
A force quit temporarily resets the state

This explains why the issue may disappear temporarily, only to return later.

Third-Party Tools Can Quietly Cause Problems

Here is something many guides miss entirely.

System-level tools can interfere with Outlook’s reply editor, including:

Text expanders
Clipboard managers
CRM plugins
Email tracking extensions

These tools hook into typing behavior. When combined with HTML rendering, they can push Outlook into freezing states.

Disabling them resolved office 365 hanging on mac when replying for multiple users, including myself during testing.

What Actually Fixes Office 365 Hanging on Mac When Replying

Based on real-world patterns, these solutions work most consistently:

Most Effective Fixes

Switch from New Outlook to Legacy Outlook
Create a brand-new Outlook profile
Reply in plain text instead of HTML
Remove or simplify email signatures
Disable third-party typing or email extensions

What Usually Does Not Work

Reinstalling macOS
Changing antivirus software
Cleaning disk space
Resetting network settings

These steps treat symptoms, not root causes.

How Searchers Want This Information Presented

People searching for office 365 hanging on mac when replying are not beginners. They want:

Confirmation they are not alone

A clear explanation of why replying is different

Pattern-based fixes, not generic advice

The most helpful articles acknowledge frustration first, then guide users through diagnosis instead of guessing.

My Personal Takeaway

Dealing with office 365 hanging on mac when replying completely changed how I view software issues. Not every freeze is a failing computer. Sometimes it is a fragile interaction between:

Rendering engines
Cached data
Email formatting
And background utilities

The Key Takings:

If Outlook freezes every time you reply, you are not imagining it.
Office 365 hanging on mac when replying is a real, well-documented behavior tied to rendering, profiles, and editor design.
With the right approach, you can fix it… and finally reply to emails without bracing for the spinning beach ball.