Is the Search in Outlook for Microsoft 365 broken? (March 2023)

[German]A short note and also a question to the readers for those affected. I have information that the search no longer works for Outlook users from the circle of Microsoft 365 customers. Microsoft is aware of the problem, but nothing can be done, according to support.


A reader report

I received feedback in a private message from Tobi Tecci on Facebook yesterday (Friday, March 31, 2023) that there were issues with Outlook for Microsoft 365. He works as an IT service provider/administrator and is faced with the fact that his customers ran into problems with Outlook. Tobi wrote me about

Hello Günter.

For all customers using MS365 apps, the search function does not work in Outlook anymore. MS support says that it is a global issue, which currently can't be solved.

Do you know the issue?

I had not heard anything from the readership here in the blog so far. There is only Florian's comment here on the German article Leitfaden von Microsoft zur Outlook-Schwachstelle CVE-2023-23397:

Hello, something else. We had to remove the patch on many computers because Outlook became unusable.

Sometimes Outlook could not be started, Outlook froze and there were problems with attachments. All these problems were solved directly after uninstalling the patch.

But this is a different error pattern and has not been confirmed by other readers. Florian suspects that it may be due to their proxy server – here I have no further feedback yet. On there is this community post with thread start on March 28, 2023, which fits the error pattern:

Happy Monday

all of a sudden this morning my search in Outlook (O365)  is not working .

no matter what I search "no results found "

Anyone else having this issue .

Yes I checked for Updates and did a power cycle .

thanks in advance

The suggestion there was to rebuild the index, which helped with this user.

A Microsoft support article

I then went to the Microsoft support page Fixes or workarounds for recent issues in Outlook for PC, where Microsoft lists issues with Outlook for Microsoft 365, Outlook 2021, Outlook 2019, Outlook 2016 and Outlook 2013.


Outlook Fixes and Issues

And indeed there is an entry No results when searching in Outlook with Suggested Searches for specific queries from March 30, 2023, which refers to Outlook for Microsoft 365. There Microsoft writes:


When users search in Outlook for Windows selecting specific queries from the Suggested Searches they see "No results". This is affecting users working with non-English versions of Windows and M365 Apps.

Not all Suggested Searches queries will fail. We are currently aware of the failures below, but other languages might be affected:


Invalid suggested query: an:""
Working query: bis:""

So it's an issue for users of a non English Outlook 365 for Windows with some search queries. Microsoft also limits that not all queries of the suggested search fail. Several languages could be affected, according to the support post.

In the support article, Microsoft writes that according to initial investigations, the problem seems to be due to the fact that the query used by the Outlook client does not match the service-level expression. As a result, the search fails. While the engineering team is investigating the issue and working on a solution, workarounds are available:

  • Users can manually modify the invalid query to get correct search results by using the above queries.
  • Users can replace the localized query (in the local language) and replace it with the English equivalent.

In addition, Microsoft states that temporarily disabling Server Assisted Search helps, as Windows Desktop Search is then used. To do this, open the following registry key in Registry Editor:


There the 32-bit DWORD value DisableServerAssistedSearch has to be set to 1. At this point I am interested if there are other affected people and if Tobi's feedback corresponds with the above support post?

Similar articles:
Patch critical EvP vulnerability CVE-2023-23397 in Outlook
Patchday: Microsoft Office Updates (March 14, 2023)
Exchange Server Security Updates (March 14, 2023)
Outlook vulnerability CVE-2023-23397 not fully patched
Microsoft Guidelines for investigating attacks using CVE-2023-23397

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2 Responses to Is the Search in Outlook for Microsoft 365 broken? (March 2023)

  1. Random User says:

    This occurred to me when searching emails on approximately 1 June 2023. I began appending
    ((folder:inbox) OR (folder:sent))
    to every search. At the time, it rectified missing search results. I still do that to today.
    It was only certain emails that it wouldn't find. Frighteningly, I could forward the emails to the same address (mine) and it STILL wouldn't find them without that suffix. Not even months later.

    To those who nod and say "bad index", no. I rebuilt it entirely. Sorry, but I did all the Level One User error suggestions.

    By the way, Outlook 365 changed in mid September 2023. For the preceding, oh, maybe 24 months, Saved Searches would not add to the MRU. Suddenly on 19 Sep 2023 it works again. If I do a search, it will appear as the first item in the dropdown now, AS IT DID, PROPERLY, TWO YEARS AGO. My last 3 are the top 3. It took them about 2 years to un**** what they did, which could have been accomplished in 10 seconds by simply rolling back the bad change, which any twelve year old programmer understands. And if anyone thinks they ever read uservoice, you're just playing with yourself. Even if you're swindled by their occasional bot responses "we recognize this and are working on a fix", the perma-BS response :)

    Note, they didn't quite fix it, despite being the "smartest tech people in the world". You used to be able to tailor the Suggested Search MRU with the delete key so you kept the ones you wanted and no others. Nope, Khan's superior intellect hasn't yet figured out how to restore that feature that wasn't broke that they so ineptly fixed.

  2. Paulo Brazilian says:

    I managed to solve the search with outlook with the tutorial
    It is

    thank you very much

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