Microsoft Loop — Mermaid Preview grayed out: "Preview" and "Split Mode" options not clickable

Question

Microsoft Loop — Mermaid Preview grayed out: "Preview" and "Split Mode" options not clickable

CORENTIN BERTEAU 60

Bonjour
Preview of 1779194356094_image.png (EN)
In Microsoft Loop, the Mermaid block displays syntax highlighting correctly, but the "Preview" and "Horizontal Split Mode" options are grayed out and cannot be clicked. Only the "Code" option is selectable, making it impossible to render the diagram visually. Our tenant has Loop enabled for all users. We could not find any setting in admin.microsoft.com or config.office.com to unlock these options. Could you please let us know if this feature requires a specific license or a tenant-side activation?

(FR)
Dans Microsoft Loop, le bloc Mermaid affiche bien la coloration syntaxique mais les options "Préversion" et "Mode Fractionné Horizontal" sont grisées et non cliquables. L'option "Code" est la seule sélectionnable. Le rendu visuel du diagramme est donc impossible. Notre tenant a Loop activé pour tous les utilisateurs. Nous n'avons pas trouvé de paramètre dans admin.microsoft.com ni dans config.office.com pour débloquer ces options. Merci de nous indiquer si cette fonctionnalité nécessite une licence spécifique ou une activation côté tenant.

Diana Schnuth 5 Reputation points

2026-05-19T13:42:47.7733333+00:00

I also have this issue. Mermaid worked fine for me two weeks ago, but failed to render starting yesterday. Another user in my tenant who has a Planner Premium license is still able to see the render option for Mermaid code blocks in Loop.
Engel - Pankow, Emiel 5 Reputation points

2026-05-19T14:10:37.4633333+00:00

I have the same problem. updated Microsoft Edge from Version 148.0.3967.54 to Version 148.0.3967.70, but this did nog fix it.
Ben Philpot 0 Reputation points

2026-05-20T08:41:09.7233333+00:00

I have the same issue with Edge. Was fine previously but today I get no previews. Version 148.0.3967.70.

Chrome 148.0.7778.168 works fine though... no wait.. auto update to 148.0.7778.179 and its broken too!

As noted by Daniel below, the Mermaid site works: https://mermaid.ai/live

If you like VS Code, that works too with side by side preview using the Mermaid extension.
Daniel 5 Reputation points

2026-05-20T09:42:51.19+00:00

It seems to be an issue with Mermaid in Loop in total.

I have the same problem in Firefox and in the Outlook app of Loop. The free Web version of Mermaid itself has no issues though.
Yasaman Dadruie 0 Reputation points

2026-05-20T13:47:37.3033333+00:00

I also have the same issue in Edge and Chrome
Vivek Chaudhary 0 Reputation points

2026-05-20T19:36:11.07+00:00

I’m experiencing the same issue. It worked a few days ago, but now when I create a new document, it’s greyed out.
Heinrich Maria 0 Reputation points

2026-05-21T10:20:30.6+00:00

I have the same problem in Edge and Chrome, and with two different tenants.
Maycon Douglas Silva Santos 0 Reputation points

2026-05-21T13:02:27.77+00:00

Same here, different tenants, different users. It was working fine 2 days ago.
Confirmed with business and IT, no changes made on their side.

Chrome, Firefox, Edge, all with the same behaviour.

Answer accepted by question author

Yuma Obata 100

Hi everyone,

In my environment, I was able to resolve this issue by clearing the browser cache. After clearing the cache and reloading Loop, the "Preview" and "Split Mode" options for the Mermaid block became clickable again, and the diagram rendered correctly.

If anyone is still experiencing this problem, please try the following:

Microsoft Edge:

https://support.microsoft.com/en-us/edge/view-and-delete-browser-history-in-microsoft-edge

Google Chrome:

https://support.google.com/accounts/answer/32050?hl=en&co=GENIE.Platform%3DDesktop

If clearing the cache alone does not work, you may also try opening Loop in an InPrivate / Incognito window to confirm whether the issue is cache-related.

Hope this helps!

Gheorghe Ursu 5 Reputation points

2026-05-22T07:14:10.5033333+00:00

worked for me, thanks
Ali Ait-Bachir 5 Reputation points

2026-05-22T13:51:49.9666667+00:00

hi, The same worked for me : clear last week of cached data.
Gilles 0 Reputation points

2026-05-26T10:07:23.7766667+00:00

Hi, thank you very much. Clearing the site's data worked for me, with a chromium based browser. Edit : it doesn't last unfortunately.

Either it only work for a few seconds or for whats seems to be minutes.

I'll switch to another app and return to loop only to find out my mermaid preview is not available anymore…
JC 5 Reputation points

2026-05-27T16:16:00.08+00:00

So clearing the cache worked for me up until today where it fails, I've had to reclear the cache and now I can only see it for a few seconds. Was there any sort of larger issue recognition from Microsoft on this @Tamara-Hu ?

2 additional answers

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Diana Schnuth 5 Reputation points

2026-05-19T13:42:47.7733333+00:00

I also have this issue. Mermaid worked fine for me two weeks ago, but failed to render starting yesterday. Another user in my tenant who has a Planner Premium license is still able to see the render option for Mermaid code blocks in Loop.
Engel - Pankow, Emiel 5 Reputation points

2026-05-19T14:10:37.4633333+00:00

I have the same problem. updated Microsoft Edge from Version 148.0.3967.54 to Version 148.0.3967.70, but this did nog fix it.
Ben Philpot 0 Reputation points

2026-05-20T08:41:09.7233333+00:00

I have the same issue with Edge. Was fine previously but today I get no previews. Version 148.0.3967.70.

Chrome 148.0.7778.168 works fine though... no wait.. auto update to 148.0.7778.179 and its broken too!

As noted by Daniel below, the Mermaid site works: https://mermaid.ai/live

If you like VS Code, that works too with side by side preview using the Mermaid extension.
Daniel 5 Reputation points

2026-05-20T09:42:51.19+00:00

It seems to be an issue with Mermaid in Loop in total.

I have the same problem in Firefox and in the Outlook app of Loop. The free Web version of Mermaid itself has no issues though.
Yasaman Dadruie 0 Reputation points

2026-05-20T13:47:37.3033333+00:00

I also have the same issue in Edge and Chrome
Vivek Chaudhary 0 Reputation points

2026-05-20T19:36:11.07+00:00

I’m experiencing the same issue. It worked a few days ago, but now when I create a new document, it’s greyed out.
Heinrich Maria 0 Reputation points

2026-05-21T10:20:30.6+00:00

I have the same problem in Edge and Chrome, and with two different tenants.
Maycon Douglas Silva Santos 0 Reputation points

2026-05-21T13:02:27.77+00:00

Same here, different tenants, different users. It was working fine 2 days ago.
Confirmed with business and IT, no changes made on their side.

Chrome, Firefox, Edge, all with the same behaviour.
Gheorghe Ursu 5 Reputation points

2026-05-22T07:14:10.5033333+00:00

worked for me, thanks
Ali Ait-Bachir 5 Reputation points

2026-05-22T13:51:49.9666667+00:00

hi, The same worked for me : clear last week of cached data.
Gilles 0 Reputation points

2026-05-26T10:07:23.7766667+00:00

Hi, thank you very much. Clearing the site's data worked for me, with a chromium based browser. Edit : it doesn't last unfortunately.

Either it only work for a few seconds or for whats seems to be minutes.

I'll switch to another app and return to loop only to find out my mermaid preview is not available anymore…
JC 5 Reputation points

2026-05-27T16:16:00.08+00:00

So clearing the cache worked for me up until today where it fails, I've had to reclear the cache and now I can only see it for a few seconds. Was there any sort of larger issue recognition from Microsoft on this @Tamara-Hu ?

Answer 1

Hello @CORENTIN BERTEAU and everyone,

I understand how confusing and frustrating this behavior can be, and I really appreciate you taking the time to share the details.

At the moment, I haven’t been able to find any official Microsoft documentation that confirms whether this is related to licensing or tenant configuration. Since multiple users are experiencing the same issue, it does suggest that a deeper investigation on the backend may be required.

Given this, I recommend reaching out to Microsoft Technical Support. Their specialists have the tools to perform more in-depth diagnostics and, if needed, escalate the case to the appropriate internal team. This will ensure your issue is formally tracked and may also help contribute to a future fix.

For business support:

Find your Microsoft 365 admin: If you don't know who the global admin is in your organization, you can find guidance here: How can I find my Microsoft 365 admin? - Microsoft Support
Submit a service request: The Global Administrator should create a support request with Microsoft to receive advanced technical assistance. For detailed instructions, see: Get support - Microsoft 365 admin | Microsoft Learn
If your organization's subscription is from a partner or reseller, contact the reseller's support provider to help open a service request on behalf of you instead.

If you discover any solutions or have additional insights, please consider replying to this thread to help others in the community.

I sincerely apologize for redirecting you to the Microsoft Technical Support Team. While I strive to assist as much as possible here in the forum, my resources are limited when it comes to backend-level diagnostics and advanced troubleshooting. Some issues require deeper technical analysis and access to internal tools that only the official support team can provide.

However, please know that you are not alone in experiencing this. I will continue to monitor this case and keep an eye on any updates. If there are any changes or new information regarding this feature, I will make sure to share them with you promptly.

If you need further assistance, feel free to reply. I'm here and happy to help!

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Answer 2

Hello @CORENTIN BERTEAU, @JC and everyone,

Thank you for continuing to share your updates and for the time you’ve spent checking your side. I understand how frustrating it must be, especially as it appears to be affecting more users.

At the moment, I haven’t been able to find any official reports confirming this behavior either. Given that the number of impacted users seems to be increasing, I would strongly recommend reaching out to Microsoft Support for a deeper investigation. If you received any confirmation from Microsoft Support Team, please don't hesitate to share with the community.

In addition, it would be very helpful if your organization’s Microsoft 365 admin could also report the issue through the Microsoft 365 Admin Center, as this can help bring more visibility to the Product team internally. Please ask your admin to follow these steps:

Sign in to Microsoft 365 Admin center.
Navigate to Health > Service health > In the Reported issues tab, Select Report an issue.

User's image

Fill in the form and click Submit to report this issue.

Your action will assist the Microsoft backend team in investigating and resolving this issue more efficiently.

I’m really sorry for the inconvenience this situation is causing. I want to be transparent that while I can monitor certain internal tools, I don’t have the ability to escalate this directly to the Microsoft Product team or access advanced backend systems for further troubleshooting.

I truly appreciate your patience and your efforts in raising this issue. Your reports are important, and I sincerely hope we’ll see clarity and resolution soon.

Thank you again for your understanding.

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Microsoft Loop — Mermaid Preview grayed out: "Preview" and "Split Mode" options not clickable

2 additional answers

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