How to fix email of outllook Home & Business 2024 on Macbook Pro OS Sonoma

Question

I used MS office 365 for several years, and just changed to use Office Home & Business 2024 these days. After I installed it & opened Outook Home & Business 2024, it showed Importing On My Computer, I let it keeping running it continuously (nearly 20 hours) until it show my disk nearly full (just 150 MB avaiable, before installing Office Home & Business 2024 still have around 120 GB) & ask Quit, then I clicked on Quit & it showed a window with Repair on Outlook Database, however, my laptop is pending. Then I re-started my laptop & opened Outlook, it showed nothing in On My Computer, also no shows Importing On My Computer, no window for Repair Outllook Database. I uninstalled Home & Business 2024, then re-installed it back for trial. The situation is same like that, nothing in On My Computure, the funtion o Import/Export or Import on My Computer is dimmed too.

I use email for working a lot. There are lots of emails in my computer for years. Email storage ups to 1TB on Macintoch HD on Macbook after many years.

Could you pls help me to fix this issue? I'm stuck in work now without email working. I need all old emails shows in On My Computer for working. I have some questions as below:

1. Does Office Home & Business 2024 occupy space on Macintoch HD when it importing On My Computer? If yes, how much it will take space on my dish for current old emails?
2. Office Home & Business 2024 work smoothly with such big email number if this issue is fixed in comparision with Office 365?
3. If this issue can't be fixed with Office Home & Business 2024, and if I return to use Office 365 back, can my old email still working normally in the past?

Thanks so much!

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Moved from Outlook | MacOS | New Outlook for Mac | For business

Answer 1

Outlook for Mac stores “On My Computer” data locally on the Mac and does not sync it to a mail server. When moving from Microsoft 365 (subscription) to Office Home & Business 2024 (perpetual), the Outlook app version changes, but the basic behavior of “On My Computer” folders remains the same.

Key points based on the questions:

1. Disk space usage for “On My Computer” data
   • For POP/IMAP accounts, items other than email messages are stored locally, and any “On My Computer” folders are stored only on the Mac, not on a server.
   • The “On My Computer” label simply indicates that the items are local to Outlook and not on a mail server; it does not correspond to Finder-visible files, but the data still occupies space on the disk.
   • When importing archives (.pst or .olm) into Outlook for Mac, the imported content is placed under On My Computer and stored locally.
   • The context does not specify an exact size formula; the local Outlook data will grow roughly in proportion to the total size of all stored mail, calendar, contacts, tasks, and notes. If there is up to 1 TB of historical mail, Outlook’s local database can also be very large and can consume most of the available disk space.
2. Visibility and use of “On My Computer” folders
   • If On My Computer is not visible in Outlook, it may be hidden:
     • Go to Outlook > Preferences….
     • Under Personal Settings, select General.
     • Clear the checkbox Hide On My Computer folders.
   • After this, “On My Computer” should appear in the navigation panes (Mail, Calendar, People, Tasks, Notes) and any imported or existing local data that Outlook can still read will show there.
3. Import/Export and “On My Computer” in new vs. legacy Outlook
   • Import of .pst/.olm into On My Computer is explicitly documented as a feature of Legacy Outlook for Mac only.
   • In the current (new) Outlook for Mac, the Import feature and direct work with “On My Computer” may be unavailable or dimmed, which matches the described behavior.
   • To work with existing .olm/.pst archives and “On My Computer” data, Legacy Outlook for Mac must be used; once imported there, the content appears under On My Computer.
4. Performance with large local mail stores
   • A very large Inbox and large local data can slow Outlook because it must synchronize and index many items.
   • One documented mitigation is to move messages from server folders to On My Computer folders to reduce server sync load, but this increases local disk usage and makes those items unavailable from other devices.
   • With extremely large data (hundreds of GB or more), performance and disk pressure issues are expected regardless of whether the license is Microsoft 365 or Office Home & Business 2024, because both use the same Outlook for Mac codebase for a given version.
5. Switching back to Microsoft 365 vs. Office Home & Business 2024
   • The subscription (Microsoft 365) and perpetual (Home & Business 2024) licenses control activation and feature set, not the fundamental storage of “On My Computer” data.
   • Existing “On My Computer” data is stored locally in Outlook’s profile/database. If Outlook can still open that profile, the data will appear under On My Computer once the folders are not hidden.
   • The context does not describe any automatic deletion of “On My Computer” data when changing license. If the profile/database is intact, returning to a supported Outlook version that can read it should allow continued use of the old mail.
6. Practical recovery steps based on the context
   • Ensure On My Computer folders are not hidden:
     1. Open Outlook.
     2. Select Outlook > Preferences.
     3. Under Personal Settings, click General.
     4. Under Sidebar, clear Hide On My Computer folders.
   • If using the new Outlook where Import is dimmed, switch to Legacy Outlook for Mac (if available in the product selection) to:
     • Import .pst/.olm archives.
     • Access and manage On My Computer data.
   • If Outlook performance is slow or the disk is nearly full, move some messages from server folders to On My Computer (or vice versa) and consider archiving/cleaning up old mail to reduce the database size.

For the specific comparisons (Office Home & Business 2024 vs Microsoft 365 performance, exact disk usage, or guarantee of recovery of all historical mail), the provided context does not include detailed metrics or version-specific behavior beyond what is summarized above.

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References:

• About On My Computer folders in Outlook for Mac
• Import email messages, contacts, and other items into Outlook for Mac
• Outlook is running slow