Control Installation and Use of New Outlook – Microsoft 365 Apps

As you may know, Microsoft introduced "New Outlook" some time ago, a new version of Outlook that resembles the web version and will eventually replace all other Outlook clients in the (near) future.

This "New" version is not equally popular with everyone, mainly due to certain limitations (such as: no full support for PST files yet – no support for classic COM plug-ins).

Starting in January 2025, Microsoft will automatically switch users of the "classic" Outlook to New Outlook.

More information can be found here:
👉 Switch to the new Outlook for Windows

For users of M365 Business Standard & Premium: from January 6, 2025.
For users of Enterprise editions: from April 1, 2026.

Note: Keep in mind that New Outlook will not work for users with only an Exchange Online or M365 Business Basic license (just like the classic Outlook client is not included in these SKUs).

More information about licensing requirements for New Outlook can be found here:
👉 How licensing works for work and school accounts in the new Outlook for Windows

Disadvantages of New Outlook

1. No Support for PST Files (Archives)

Problem: You cannot import or open PST files (local email archives) in New Outlook.
Impact:
- Users who rely on large local archives cannot access them directly.
- This can be challenging for organizations that store old emails locally.
Solution:
- Transfer archives to Online Archiving (Exchange Online Archive) or use a OneDrive integration for large files.

2. No Support for Direct Attachment Editing

Problem: Attachments must first be saved to OneDrive before you can edit them.
Impact:
- This requires extra steps and is less intuitive than directly editing in classic Outlook.
- It can slow down workflows if users need to quickly modify and return documents.
Solution:
- Use OneDrive for Business as the default storage location for shared files.
- Communicate to users how to efficiently manage attachments.

3. Less Flexibility in Dragging Attachments

Problem: Dragging attachments to and from New Outlook does not always work smoothly.
Impact:
- Users accustomed to dragging attachments between emails or to desktops may find this limiting.
Solution:
- Use the "Save As" or "Copy to" option for attachments.

4. Security and Attachment Scans

Problem: Stricter security controls on attachments may lead to delayed downloads or blocks.
Impact:
- Attachments with macros or unknown file types may be blocked.
- This prevents malware but can be frustrating for legitimate files.
Solution:
- Ensure users share attachments via OneDrive links or SharePoint, making files easier to scan and open securely.

5. Loss of Advanced Settings

Problem: Some advanced configurations and settings from classic Outlook are not supported.
Details:
- Limited rules and alerts.
- Fewer options for custom views and filtering.
Impact:
- Users who have significantly customized their workflows cannot fully transfer them to the new version.

Benefits of New Outlook with Attachments

Automatic Storage in OneDrive – You are less likely to lose attachments, as they are automatically saved to the cloud.
Real-Time Collaboration – Attachments stored in OneDrive can be edited by multiple people simultaneously.
Bypass Size Restrictions – Instead of emailing large files directly, Outlook automatically generates a shared link.