Hello, I am experiencing an issue with Microsoft 365 Copilot where code blocks are not rendering correctly. When Copilot generates a response containing a code block, the code block area only shows animated/pulsing placeholder lines and the content never appears. Regular text render normally and inline code snippets renders sometimes, but full code blocks do not. Environment The issue occurs in: Microsoft 365 Copilot in a web browser (Microsoft Edge) Microsoft 365 Copilot desktop application What I have tested Repaired the Copilot application from Windows Settings Cleared browser cache and site data Tested with different chats/prompts Verified that the user has the required Copilot license assigned Verified that no obvious Copilot-related policies or restrictions are blocking access Signed out and back in Restarted the device Additional observations Standard text responses render correctly. Inline code formatting renders correctly sometimes , but not always. The affected area remains as pulsing/loading placeholder lines indefinitely. The behavior is consistent across both the browser and desktop app for those affected. Has anyone else encountered this issue recently, or is this a known problem with the Copilot client rendering code blocks? If there are any logs, diagnostics, or additional troubleshooting steps that Microsoft recommends, I would be happy to provide more information.

I found this issue fixed itself in the desktop app simply by turning off the New Design toggle in the top right corner of the app.

I disabled two extensions in Edge and that seems to have solved it. Namely: https://microsoftedge.microsoft.com/addons/detail/saml-wsfederation-and-o/boffpaecgbbojpkboijhbmhecoefdehi https://microsoftedge.microsoft.com/addons/detail/centro-365/ampgmpmlobbbhjoplcbdfcgplbkbmked

Problem with codeblocks not rendering in Microsoft 365 Copilot

Ole Slupphaug 60

Hello,

I am experiencing an issue with Microsoft 365 Copilot where code blocks are not rendering correctly.

When Copilot generates a response containing a code block, the code block area only shows animated/pulsing placeholder lines and the content never appears. Regular text render normally and inline code snippets renders sometimes, but full code blocks do not.

Environment

The issue occurs in:

Microsoft 365 Copilot in a web browser (Microsoft Edge)
Microsoft 365 Copilot desktop application

What I have tested

Repaired the Copilot application from Windows Settings
Cleared browser cache and site data
Tested with different chats/prompts
Verified that the user has the required Copilot license assigned
Verified that no obvious Copilot-related policies or restrictions are blocking access
Signed out and back in
Restarted the device

Additional observations

Standard text responses render correctly.
Inline code formatting renders correctly sometimes, but not always.
The affected area remains as pulsing/loading placeholder lines indefinitely.
The behavior is consistent across both the browser and desktop app for those affected.

Has anyone else encountered this issue recently, or is this a known problem with the Copilot client rendering code blocks?

If there are any logs, diagnostics, or additional troubleshooting steps that Microsoft recommends, I would be happy to provide more information.

NxKo 5 Reputation points

2026-08-06T13:44:52.7033333+00:00

Still doesn't work, now Even english causes problems. Microsoft is not what it used to be, enshitification of products is real, even for premium users
Alexandros Kanakaris 41 Reputation points

2026-08-06T19:54:29.22+00:00

I had the same issue. I disabled the following extensions on Edge.

https://microsoftedge.microsoft.com/addons/detail/centro-365/ampgmpmlobbbhjoplcbdfcgplbkbmked

https://microsoftedge.microsoft.com/addons/detail/saml-wsfederation-and-o/boffpaecgbbojpkboijhbmhecoefdehi

The problem seems to be resolved (fingers crossed).
John H. Embretsen 0 Reputation points

2026-08-07T08:07:17.96+00:00
I observed the same issue, and changing from Norwegian to English (US) language in browser settings fixed it for some time. Now it is back regardless of language settings.

I have only tested this in Chrome for now, in one network.

I have run some tests along with Copilot Chat, and have found the following:

Some formatted content blocks remain displayed as gray animated placeholder lines indefinitely.

The issue is intermittent and affects only some blocks within a response.

The missing content is not available through Ctrl+A / Copy, indicating the content never reaches the rendered DOM.

Browser console (F12 --> Console)

Observed repeatedly:

Virtualizer index less than zero, cannot render child rows

Virtualizer index less than zero, cannot update child array

Also observed:

An iframe which has both allow-scripts and allow-same-origin...

Hovering over links in the Copilot response caused additional console messages to appear, including:

The current string map is empty.

The string is probably resolved too early, at import time.

Key: datetime-formatting.timeFormatStrings.monthAndDate

Unclear if this is related or not.

Experiments performed

Test 1

Different formatting types.

Results:

Plain text: rendered

Tables: rendered

XML: rendered

JSON: rendered

Shell code block: failed

Test 2

Additional formats.

Results:

bash: rendered

shell: rendered

sh: rendered

sql: rendered

yaml: rendered

xml: rendered

python: rendered

javascript: rendered

Failed:

powershell

json

no-language code block

This contradicted the initial hypothesis that the issue was shell-specific.

Test 3

Duplicate-content test.

Three identical blocks of the same type were placed in one response.

Results:

Identical block #1: failed

Identical block #2: rendered

Identical block #3: rendered

The same pattern was observed for JSON and PowerShell blocks.

This demonstrates that identical content can both succeed and fail within the same response.

Test 4

Position test.

Ten identical blocks:

A: rendered

B: rendered

C: rendered

D: rendered

E: rendered

F: failed

G: rendered

H: rendered

I: rendered

J: rendered

Only one of ten identical blocks failed.

Conclusion

The issue does not appear to depend on:

content

language tag

syntax type

special characters

The behavior is consistent with an intermittent client-side rendering failure, virtualization issue, or component lifecycle problem.

7 answers

Craig Knights 0 Reputation points

2026-08-07T13:47:04.3133333+00:00

I found this issue fixed itself in the desktop app simply by turning off the New Design toggle in the top right corner of the app.
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Dade, Dustin 0 Reputation points

2026-08-07T14:39:54.61+00:00

Unfortunately it appears that on at least the Mac standalone app they have already removed that option, or never gave this version the option to turn off the new design.

Craig Knights 0 Reputation points

2026-08-07T17:03:02.04+00:00

that's unfortunate, it's not a perm fix as I've discovered but swapping between the new and old design causes the existing chat to refresh it without regenerating, which reveals the pending code and which admittingly, sucks but its a work around, at least for some
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Alexandros Kanakaris 41 Reputation points

2026-08-06T19:56:44.88+00:00

I disabled two extensions in Edge and that seems to have solved it.

Namely:

https://microsoftedge.microsoft.com/addons/detail/saml-wsfederation-and-o/boffpaecgbbojpkboijhbmhecoefdehi

https://microsoftedge.microsoft.com/addons/detail/centro-365/ampgmpmlobbbhjoplcbdfcgplbkbmked
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Problem with codeblocks not rendering in Microsoft 365 Copilot

Environment

What I have tested

Additional observations

Test 1

Test 2

Test 3

Test 4

7 answers

Your answer