Microsoft has released Security Updates (SUs) for vulnerabilities found in:
Exchange Server Subscription Edition (SE)
Exchange Server 2019
Exchange Server 2016
SUs are available for the f...
Updated Sep 24, 2026
Version 4.0
Blog Post
Is anyone else having search issues in Outlook and OWA after this update?
I think we're also experiencing the issue where the search in Outlook/OWA isn't finding recent emails. We didn't notice it right away because we still had the old workaround (https://support.microsoft.com/en-us/topic/incomplete-search-results-after-installing-an-exchange-server-2019-update-96ae2ef0-4569-4327-8d0c-8a3c1abdc1f6) in place.
However, it takes a very long time for new emails to be indexed.
Yesterday morning, I received an email that I couldn’t find using the search function. I triggered the retry for my mailbox, but it wasn’t processed until late at night. This morning, I was finally able to find the email using the search function.
We are running Windows Server 2019, so updating .net framework ist not an option for us.
May I ask is this Outlook search issue affecting mailboxes hosted onprem only or is it also affecting Exchange Online mailboxes in hybrid Exchange environments?
Yes we are seeing the same exact problem, users started reporting search issues today, we are also running Exchange SE on Server 2025
Same as the others .. seeing BigFunnelNotIndexedCount exploded on all mailboxes
Is there any known workaround to get search working again at this point?
I looked into this a little bit just now. About .NET 4.8 comment, this appears to be completely unrelated to this issue. Since we are on server 2025, .NET 4.8.1 comes server 2025 by default.
We have 4 SE exchange servers with DAG setup to replicate mailboxes between all of them. On only 2 of our exchange servers I am seeing the following log over and over in these 3 log paths:
C:\Program Files\Microsoft\Exchange Server\V15\Logging\Search\NotificationsContentIndexingConnection\*.log
C:\Program Files\Microsoft\Exchange Server\V15\Logging\Search\OnSaveContentIndexingConnection\*.log
C:\Program Files\Microsoft\Exchange Server\V15\Logging\Search\RetryContentIndexingConnection\*.logERROR: "An error has occurred.,FailedToConnect: skip adding Poi,,,146902,2,MSExchangeMailboxAssistants.exe"
What I did as a test was migrated the mailbox DBs on one of these 2 servers to another server and reboot the exchange server. Upon rebooting, I migrated those mailboxes that have activation preference 1 back to this server and I haven't seen these error logs show back up in those log locations above and I saw the BigfunnelNotIndexedCount go down by a few hundred on one of the mailboxes on this DB .. but now it's staying at the number assuming because of all the emails flagged as PermanentFailure=true and won't be retried for reindexing?
I then ran the Troubleshoot-ModernSearch.ps1 script against one of these mailboxes and the BigfunnelNotIndexedCount is exact count match for all the emails that are stuck with PermanentFailure=true all have the same reason "FailedToConnect: skip adding Poi" on them, how do we get these to requeue and re-index?
Not sure if indexing will continue working for new emails received or if it will hit the issue again but I'm just posting what I am seeing from our exchange environment. Hopefully this helps MS with the fix
Since you are running Server 2025, you can upgrade .NET 4.8 to 4.8.1. That seemed to solve the issue for others experiencing the issue. I can't since I am running Server 2019. The only thing that has temporarily helped is restarting the servers, which helps bring down the BigfunnelNotIndexedCount from ridiculously high numbers (+500) to less than 200. Eventually, the number goes back up, and I reboot again. MS needs to get on top of this! What are folks running Server 2019 supposed to do since we can't upgrade .NET?
See my issue below. My solution was to upgrade .NET 4.8 to 4.8.1. New emails are now being found again. However, .NET 4.8 is listed as supported. :/
The only problem is that all emails received in the meantime are not not indexed (status “IndexingAttemptCount 7” + “IsPermanentFailure true”).
This can probably only be fixed with a Mailbox MoveRequest. Definitely not funny.
Same here, got BigFunnelNotIndexedCount in the thousands after the update
Mine as well. Is MS going to release a follow-up update for this?
- Nino_Bilic
Microsoft
We are trying not to; howver - while we have seen that folks are saying that .NET framework upgrade solves the problem, we cannot get a repro of the problem with framework 4.8 to begin with. Someone will need to open a ticket on this...
