I've got a frustrating issue that's gone on for a long time now, for one of our users where I work. She's constantly had issues doing email searches in Outlook on her Macbook Air. I know there was recently a bug with Mojave related to this:
But her issues go back far earlier .... and she's currently on 10.14.6 and still having issues, despite following the steps outlined here in blue:
What happens is, right after she does the step to delete the index and force it to rebuild, search will "mostly work", except not always locating all instances of what she's searching for, such as all email from a certain person. After it runs for a few weeks, it gets progressively worse at returning reliable search results. It may randomly pull up a few recent messages that match a query and then a few random messages from 1-2 years earlier -- but misses most of them in between.... things like that.
We don't have any antivirus software loaded on the computer, which is one thing I can think of that could potentially interfere otherwise. Running out of ideas. Has anyone else encountered this? She can use the web based Outlook and searching from there works perfectly.
But her issues go back far earlier .... and she's currently on 10.14.6 and still having issues, despite following the steps outlined here in blue:

Outlook for Mac support tools. - Outlook
Describes some useful tools for Microsoft Outlook for Mac.
docs.microsoft.com
What happens is, right after she does the step to delete the index and force it to rebuild, search will "mostly work", except not always locating all instances of what she's searching for, such as all email from a certain person. After it runs for a few weeks, it gets progressively worse at returning reliable search results. It may randomly pull up a few recent messages that match a query and then a few random messages from 1-2 years earlier -- but misses most of them in between.... things like that.
We don't have any antivirus software loaded on the computer, which is one thing I can think of that could potentially interfere otherwise. Running out of ideas. Has anyone else encountered this? She can use the web based Outlook and searching from there works perfectly.