Specific addresses not showing in desktop app autocomplete list

Question

We are using 64-bit Outlook and Exchange Online in Microsoft 365.

I have a user with a peculiar issue. When typing the name of a few people he emails quite often, their name/address does not appear in his autocomplete list. The most peculiar thing is that this only happens using the Outlook desktop application. They show up when using his mobile device, as well as in OWA. It happens in both active and cached Exchange modes. It also happens on a completely different computer (I logged him into a new laptop to see if the issue persisted there given that it seemed to only be happening in his laptop's Outlook client). However, I sent a test email to my personal address from his local Outlook and that address now shows up in his autocomplete, so new entries can be added (there are a bunch of things that he says are showing up that he's sent to since first noticing it with these users). In case it's relevant, both of the users he's mentioned are at the same company. I don't know if that matters, as there are other users at that company that show up fine in his autocomplete. All of these users (both working and non-working) are in his Contacts. For the users who aren't automatically populating, CTRL+K or Check Names resolves them to their associated contact. I've also tried sending a test email myself to one of these individuals, and their address now shows in my autocomplete. I'm not quite sure how to proceed here. We've cleared the autocomplete, but these just will not match when typing. It's not a huge deal to me, but it's getting annoying to the user as these are users he's constantly in contact with.

Answer 1

Maybe you can first close outlook and wait for 15 seconds. go to the folder: C:\Users\ %username%\AppData\Local\Microsoft\Outlook\RoamCache search for the lates version of Stream_Autocomplete_0_muchcharacters.dat Rename that file to filename.bak and open outlook. The autocomplete file wil be downloaded from the cloud, test it again. Maybe you have to reopen outlook 2 times before it should work again.

Answer 2

Hi @Joe Grover ,

From your description, it seems that the problem only occurs on the user's old computer.
What version of outlook client is having this problem?
In this case, it is recommended you try the following troubleshooting:
1.Check if the issue is related to some third-party add-ins, run Outlook in safe mode: Right-click the Start button, and click Run. Type Outlook.exe /safe, and click OK.
2.Remove the specific contacts and re-add them again.
3.Repair office from Control Panel
4.Create a new profile and re-add the account.

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