Date/time format

Dear @Harald-René Flasch, 

Thank you very much for the detailed explanation and for taking the time to test across different language and region settings.

I did some additional testing and noticed the following. When using English (Austria) or German, both the date/time picker and task details consistently show a 12-hour format. With English (United Kingdom), the behavior is different. The picker still shows a 12-hour format when creating a task, but after saving and reopening it, the detail view switches to a 24-hour format.

In the meantime, you can consider these workarounds:

Option 1: Use Classic Outlook tasks

This option provides the most reliable behavior if consistent regional formatting is important.

Open Classic Outlook > Select File > Options > Go to Tasks > Uncheck Open tasks in the To Do app.

Restart Outlook.

Alternatively, if the banner appears in the Tasks view, select Keep using Tasks to remain in the classic Tasks experience.

This version typically respects Windows regional settings, including 24-hour time format and Monday as the first day of the week.

Option 2: Adjust language and region in New Outlook

This option may partially improve the experience but does not fully resolve the inconsistency.

Open New Outlook > Go to Settings > Navigate to General > Language and time.

Set the language to English (United Kingdom).

Save the changes and restart Outlook.

Please note that even after this adjustment, the inconsistency may still remain. The date and time picker may continue to display a 12-hour format, while the task detail view shows a 24-hour format.

I completely understand how these inconsistencies in the New Outlook can feel disruptive. It’s not just about aesthetics; these differences can genuinely affect how smoothly you work and navigate your day.

I’m really sorry, I know this isn’t the outcome you were hoping for. As a forum moderator, I hope you understand that I don’t have the ability to modify or escalate product issues directly. However, I strongly recommend submitting your feedback through the Outlook (new) · Community portal. This is the most effective way to ensure your voice reaches the product team and can be considered for future improvements. 

Once you've submitted your feedback, feel free to share the link here in the comments. I’ll be happy to upvote it to help bring more visibility. If you prefer, I can also submit this great idea on your behalf. Just let me know, and I’ll post it for you and share the link once it’s published. I’m here to help ensure your feedback gets the attention it deserves.

Additionally, as other users have raised similar concerns and may not be aware of where to share their feedback, I hope this response helps clarify the situation and suggests a potential next step. Highlighting this information can make it more visible to others in the community who may be facing the same issue, making it easier for them to find guidance and contribute their feedback as well.

Thank you again for your patience and for clearly outlining your findings. This kind of feedback is very helpful in highlighting areas that need improvement.

I got the answer from another forum and like to share it here:

There's two different "todo apps":

• Outlook Tasks (the legacy app that displays everything correctly
• Microsoft Todo (the modern app, ignoring regional settings...)

When adding the "Outlook Tasks" I get following warning:

I hope that Microsoft will fix this some day...

Dear @Harald-René Flasch, 

Thank you for sharing your concern.  

This behavior occurs because different Microsoft 365 components read regional, language, and time settings from different sources rather than from a single global configuration. Below are the steps that can help verify and align those settings as much as possible. 

Notes: 

• Please note that some of these steps were already mentioned earlier by Q&A Assist. I am including them again here, along with screenshots and brief instructions, to ensure everything is configured correctly. 
• Since your post is tagged for the new Outlook app, the instructions above reflect that version. If you are using classic Outlook instead, feel free to tell me and I will provide the exact steps.  
• Before starting, I recommend ensuring that Windows, Microsoft 365 apps and your web browser are fully updated. 

Step 1: Confirm Windows time format 

I understand that you have already completed this step. The screenshot below is provided only to help confirm that the settings are configured correctly. 

Step 2: Verify Calendar settings in Outlook on the web 

Open Outlook on the web and switch to Calendar. 

Open Settings, then confirm: 

• First day of the week is set to Monday.

• Under General > Language and time, the region, date format, and time format are set correctly. 

These settings influence Calendar behavior and some task related views. 

Step 3: Align Microsoft 365 account language and time zone 

Some Microsoft 365 web apps read settings directly from the Microsoft account profile. 

Open an InPrivate or Incognito browser window. 
Sign in at https://www.office.com using the affected account. 

Select Apps > Choose open Word > Settings > Under Language and time zone, choose "Change your language". 

Next, confirm that the region and date and time format are set correctly. 

Step 4: Check Excel for the web regional settings 

The Date Picker format depends on both per user settings and the SharePoint site where the file is stored. 

Open Excel for the web. 

Open a file. 

Go to File > Options > Regional Settings. 

Confirm the regional format. 

This setting overrides the SharePoint site regional settings for your session. The preference is stored using a third-party cookie. 

Note: If third party cookies are blocked in the browser, Excel for the web cannot remember this preference and may revert to the default format. 

Next, you can set the preferred regional format in Excel for the web:

• After changing settings: 

If any Microsoft 365 language or time zone settings were updated, it can take up to 24 hours for all web apps to fully reflect the changes. 

If the old format still appears after waiting, you can try clearing the cache in your browser or desktop apps: 

1/ For New Outlook desktop app:  

Close the Outlook app completely.     

Open the Run dialog by pressing Windows + R.     

Type or paste the following command and click OK:     

olk.exe --devtools     

The new Outlook will open (you may need to sign in), and the DevTools window will appear.     

In DevTools:      

Click Application on the toolbar.     

Clear local storage cache: Under Storage, find https://outlook.office.com under Local Storage, right-click it, and select Clear.     

Clear cookies: Under Cookies, locate https://outlook.office.com., right-click it, and select Clear.     

Close the DevTools window.     

Once completed, the cache for the new Outlook will be cleared. Please note that this process removes temporary files, including saved login credentials, so you may need to sign in again.  

2/ For web apps 
Open your browser settings and clear cached data. 
Select the option to clear data for all time to ensure no outdated preferences remain. 

As community moderators, we kindly ask for your understanding that our access to internal development details is limited. Our primary role is to guide users toward the appropriate resources and support channels. While we may not have visibility into performing deeper backend analysis, we’ll continue doing our best to support you within the scope of our responsibilities.  

I hope this information is helpful. Please feel free to let me know whether you are using the new Outlook for desktop, Outlook on the web, or classic Outlook and share the outcome after completing the steps above. 

Thank you for your patience and understanding. 

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