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Outlook for Mac show 4294967295 unread messages

Anonymous
2025-03-16T14:43:24+00:00

Hi,

For about 2 weeks now, Outlook for Mac started to show 4294967295 unread messages for a inbox I have with Microsoft365 business account. I have found a previous post with an almost identical number, except it was 4294967296 :). But there wasn't ant fixes appliable since it was on Windows. The problem is that I could't fount the location of the .ost file to delete it. If I delete the account and re-add it later, the problem re-occur. I do't know the behavior (that its, if when I delete the account it also deletes the .ost file or it kept it on the hdd). Anyway, what I did so far:

  1. Delete the account
  2. Add again. it worked for 2 days, then again it show 4294967295 unread messages.

Outlook | MacOS | New Outlook for Mac | For home

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  1. Anonymous
    2025-03-19T18:37:55+00:00

    Nope, the support team closed the ticket as known bug without solutions :) They said to use Legacy Outlook.

    4 people found this answer helpful.
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  2. Anonymous
    2025-03-17T15:03:13+00:00

    The issue seam to affect only New Outlook. I have switched to Legacy Outlook and no more billions of unread emails. So, my guess is that somehow .ost files or whatever it is using on Mac got somehow corrupted, but I couldn't find the exact location to delete it and let it regenerate. In the /users/myusername/library/group containers/UBF8T346G9.Office/ the are only meaningless folders with subfolders from 1 to 10.

    2 people found this answer helpful.
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  3. Anonymous
    2025-03-17T09:50:51+00:00

    So, it lasted less than 24 hours.

    Image

    2 people found this answer helpful.
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  4. Anonymous
    2025-03-19T18:28:50+00:00

    Running into this same issue. Have you found a resolution yet?

    1 person found this answer helpful.
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  5. Anonymous
    2025-03-16T18:44:27+00:00

    Hi,

    Thanks for the reply. I have tried them all. only deleting the profile seemed to have worked. Let's see how much will this last.

    1 person found this answer helpful.
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