Outlook Encounters search problem after Windows 10 security patch confirmed

Microsoft has confirmed an issue with Outlook that was triggered by the latest security update for Windows 10, version 21H2. Users noticed after Patch Day in December that the search in Outlook for Microsoft 365 no longer works properly. The error is reminiscent of a similar bug in Outlook in connection with Windows 11, which Microsoft fixed a few weeks ago with a software update. With Windows 10, the company is not quite ready – so far there is only a message that the problem is known and investigated.

Release KB5008212

Users reported that they were getting unexpected results when searching in Outlook. For example, newer e-mails are not shown in the search results even though they contain the keywords of the search. Exactly what causes the error is not yet known, Microsoft is still working on it. The only thing that is clear is that it has to do with the latest Patch Day update from December 2021. That’s what it’s been saying recently published support document:

Problem and investigation

• After installing update KB5008212, newer emails might not appear in search results.
• We are currently investigating this issue. We will update this article as more information becomes available.
• The workaround for this problem is to turn off Windows Desktop Search so that Outlook uses built-in search. The built-in search shows the following to indicate that it is not using the Windows Search Service:
• “Search performance is being affected because a group policy has disabled the Windows search service.”

Alternatively, the problems can be avoided by uninstalling the latest security update KB5008212. However, this is not recommended, as these are security-relevant changes.