Nov 16 2022 03:27 AM
Hello everyone.
I have a question regarding Exchange Online and Outlook on the desktop client.
Our customer wants to migrate an old pop3 web server to Microsoft 365, so I will upload all desktop client's outlook pst to exchange online. Use network upload to import PST files - Microsoft Purview (compliance) | Microsoft Learn
When PC clients open the new Outlook profile (desktop version), will they download all entire emails or just the headers?
Because the customer has a slow internet connection and if the pc clients download all the entire emails there may be bandwidth saturation.
Thanks in advance.
Feb 01 2024 08:30 PM
Hi Matt887,
Great question! When migrating PST files to Exchange Online using the network upload method, the behavior of Outlook desktop clients largely depends on your mailbox caching settings. Here's a breakdown:
Online Mode:
If the Outlook profile is set to "Online Mode," it means emails are directly accessed from the server. In this case, only headers are initially downloaded, reducing the impact on bandwidth.
Cached Exchange Mode:
On the other hand, if the profile is configured with "Cached Exchange Mode," Outlook will download a copy of the entire mailbox to the local machine. This provides users with offline access to emails but might lead to bandwidth saturation during the initial sync.
Given your concern about bandwidth. I suggest to use "Online Mode" for users with high-speed internet. Stagger migration for smoother transitions. Initially set profiles to "Online Mode"; switch to "Cached Exchange Mode" post-migration.
If you are wishing to know the other methods, follow these helpful guide: PST to Office 365 Migration and I found a helpful thread it can help you with PowerShell command while importing PST to office 365. Here is the thread to post: Import PST to Office 365 using PowerShell Command
Feb 04 2024 03:59 PM