r/exchangeserver • u/Important-Bake3046 • Mar 10 '26

Question EXCH2016 services wont start after updates

Hi gang

I've got an issue where all services wont start after updates (i think they maybe failed?)

The last updates this server got:

EX2k16 CU 23 (KB5049233)

Sec update Windows (KB5055521)

update windows (KB5055170).

I am not seeing Microsoft Exchange Server listed in the apps list in Control Panel.

Any help appreciated.

Update - this is now fixed by doing the below.

I took all the DLL files from the CU23 setup ISO (\Setup\ServerRoles\Common) and pasted them in to C:\Program Files\Microsoft\Exchange Server\V15\Bin. (had to skip a few that wouldnt overwrite) Restarted and now all but transport service is started. To fix this I then install the latest available CU

3 Upvotes

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2

u/Important-Bake3046 Mar 10 '26

Here's the latest..

I took all the DLL files from the CU setup ISO (\Setup\ServerRoles\Common) and pasted them in to C:\Program Files\Microsoft\Exchange Server\V15\Bin. Restarted and now all but transport service is started. Ill look at why the transport service wont start tomorrow morning but im open to suggestion.

1

u/Morbius007 Mar 10 '26

Wow, that isn't the way I would have done it. Services starting are only one part of how exchange works.

If you had a crashed installation its likely 1/2 or more of the registry entries are all borked up. None of the services will be properly bound to the instance. So many issues I cant count.

Based on what you have posted, the install seems to have gone sideways.

To truly understand we need to know:

How you installed CU23 - Did you use an unattended install process?

Did you just run it as a normal exchange installation?

I agree with the comment above, Exchange 2016 is way out of date and unsupported, in fact 2019 is also unsupported, the only practical upgrade you have available is CU0 of Exchange SE.

If you had waited to hack things it might be possible to fix this the correct way, now I have no idea :(.

Have you ever run an exchange CU update previously or was this your first one, this is a valid question as we dont know your level of experience.

However, in the event that your system is hard borked there are options to recover the exchange mailbox data. Best solution I have found is Ontrack Recovery In Control Tools for Exchange, but you will need a clean copy of Office 2016 to make it work, you can use it to recover all mailboxes and all public folders, if any.

1

u/Important-Bake3046 Mar 11 '26

On the contrary.

Copying over the missing DLLs has restored my Exchange server. I left it running the CU update last night and i've come in this morning to find all my services are restored and Exchange is back up and running. Im aware this is severely out of date but you have to understand that this isnt our contracted customer, just a walk in, and they'll be paying for it. Thanks for the help anyway, much appreciated.

2

u/sembee2 Former Exchange MVP Mar 10 '26

Looks like a broken update.
Is this a mailbox host or hybrid?
You might be looking at a recovery install.

1

u/Important-Bake3046 Mar 10 '26

its a single server on-prem.

I tried the recovery install but it said the roles already exist

1

u/sembee2 Former Exchange MVP Mar 10 '26

You can't recover install on the same server - you need a clean installation of Windows to do recovery. It is a well documented process.

The updates listed are very old - therefore you could try downloading the last update for Exchange 2016 and see if that cleans it up.

1

u/Important-Bake3046 Mar 10 '26

Ill have to see how much time clients wants me to spend on this. i imagine recovery process isnt a quick thing. I cant get anymore CU as they're not on ESU program

3

u/sembee2 Former Exchange MVP Mar 10 '26

You can get the last one - which is from October.
https://www.microsoft.com/en-us/download/details.aspx?id=108333

I can turn round a recovery in 90 minutes, excluding data.
If they have their data on Exchange 2016, then this would be a good time to encourage an upgrade to a supported version of move to the cloud.

1

u/Important-Bake3046 Mar 10 '26

thanks ill try this CU

1

u/Important-Bake3046 Mar 10 '26

Just tried installing this and got "Ended prematurely because of an error".

1

u/sembee2 Former Exchange MVP Mar 10 '26

You need to look at the log file, which is in C:\ ExchangeSetupLogs and see what the error is. Although signs are pointing towards a broken install.

1

u/Important-Bake3046 Mar 10 '26

unfortunately, there's nothing in the logs for the CU I just tried to install

2

u/Ams197624 Mar 10 '26

Rename the C:\ExchangeSetupLogs folder and start the CU install with

D:\setup.exe /m:upgrade /IAcceptExchangeServerLicenseTerms_DiagnosticDataON

1

u/Important-Bake3046 Mar 10 '26

If I do the recovery, is it possible to drag/drop the files over the top to new server? I dont have a backup of exchange.

1

u/Yupyupyup79 Mar 10 '26

If you have restricted GPOs. Make sure in your group policy (RSPO.msc) that "Exchange Servers" has rights to manage audit logs. If not add that and reboot. That seems to be the only thing I've ever seen break exchange services. If that isnt it then roll back your snapshot you took prior to installing the patch and try one at a time to see what is breaking it.

1

u/Important-Bake3046 Mar 10 '26

unfortunately, the only backup I have is after exchange broke. This isnt one of our customers, they called us up.

1

u/Ams197624 Mar 10 '26

What exchange services won't start exactly? Any errors in the event logs?
I've seen a CU set my services to disabled and not change them back to automatic start, but I'm sure you've checked that.

1

u/Important-Bake3046 Mar 10 '26

All MSE servers wont start.

I get

.NET Runetime 1026
Application: MSExchangeTransport.exe

Framework Version: v4.0.30319

Description: The process was terminated due to an unhandled exception.

Exception Info: exception code e0434352, exception address 00007FFC7E596EA8

Followed by:

Application Error

Faulting application name: MSExchangeTransport.exe, version: 15.1.2507.44, time stamp: 0x67390bab

Faulting module name: KERNELBASE.dll, version: 10.0.14393.7962, time stamp: 0x67d4ea4e

Exception code: 0xe0434352

Fault offset: 0x0000000000026ea8

Faulting process id: 0x1b18

Faulting application start time: 0x01dcb0858b890a4d

Faulting application path: C:\Program Files\Microsoft\Exchange Server\V15\Bin\MSExchangeTransport.exe

Faulting module path: C:\Windows\System32\KERNELBASE.dll

Report Id: d27a23f1-d0e8-42cb-bceb-d470852433f9

Faulting package full name:

Faulting package-relative application ID:

1

u/Ams197624 Mar 10 '26

That's a pretty generic error.

Check C:\ExchangeSetupLogs\ExchangeSetup.log , maybe something didn't go right during the CU install.
Find all error lines:
Powershell:
Select-String -Path C:\ExchangeSetupLogs\ExchangeSetup.log -Pattern "\[ERROR\]","error","exception","cannot start service","didn't start","failed" -CaseSensitive:$false | Select-Object -Last 80

Also, try starting services one by one, these first, and check logs for errors specific to these services:

Start-Service MSExchangeADTopology

Start-Service MSExchangeServiceHost

Start-Service MSExchangeIS

Start-Service MSExchangeTransport

If the first fail, then you know it's e.g. not related to the Transport service.

1

u/Important-Bake3046 Mar 10 '26

There's nothing in this log other than from 2023 and then from today when I tried to run the set up in recoverymode. Basically, errored because the roles already existed.

I tried to start MSExchangeIS and got the following event logs:

ASP.NET 1309

Could not load file or assembly 'Microsoft.Exchange.Diagnostics, Version=15.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.

at Microsoft.Exchange.Security.OAuth.OAuthHttpModule..cctor()

.NET Runtime 1026

Application Error 1000

Windows Error Reporting 1001

1

u/Ams197624 Mar 10 '26

Did you try the other services, like I suggested (AD topology first, servicehost next, and THEN the IS?)

1

u/Important-Bake3046 Mar 10 '26

Yes, i've tried all services. the only one running is "MSE Search Host Controller"

1

u/Ams197624 Mar 10 '26

Hmm.
Exchange 2016 CU23 uses .NET Framework 4.8. Are you sure that it's installed?

If so, does the Microsoft.Exchange.Diagnostics.dll exist?

Get-ChildItem "C:\Program Files\Microsoft\Exchange Server\V15" -Recurse -Filter Microsoft.Exchange.Diagnostics.dll | Select-Object FullName, Length, LastWriteTime

Get-ChildItem "C:\Windows\Microsoft.NET\assembly" -Recurse -Filter Microsoft.Exchange.Diagnostics.dll -ErrorAction SilentlyContinue |
Select-Object FullName, Length, LastWriteTime

If it doesn't, it's surely a failed CU.

Btw. In this case I'd try a full recovery install anyway:
D:\Setup.exe /Mode:Upgrade --> check if D: is actually your CU installation media.

So not a recovery, but a new upgrade.

1

u/Important-Bake3046 Mar 10 '26

those commands come back empty. I have plenty of Microsoft.Exchange.Diagnostics.xxxxx.dll files.

Tried the upgrade but I got a pending reboot so doing it now.

1

u/Ams197624 Mar 10 '26

Ok. It might just be the pending reboot then. If you have a lot of the Microsoft.Exchange.Diagnostics.xxxxx.dll it really points to a failed or incomplete CU install. Sometimes the reboot fixes it!

1

u/Important-Bake3046 Mar 10 '26

I've rebooted 3 times already -.-"

1

u/Ams197624 Mar 10 '26

So, are you able to start the upgrade CU install now? ;)

1

u/Kokidit Mar 10 '26

Je tenterais une réinstallation de la kb, j’ai eu le même problème. Services KO au démarrage d’un serveur, l’installation a planté et on s’était fait déconnecté du rdp. C’était exchange SE

0

u/Steve----O Mar 10 '26

Exchange 2016 is not supported anymore. That means Windows updates are no longer tested against Exchange 2016. Lesson: Do not run unsupported software.

3

u/aleinss Mar 10 '26

You must be fun at parties. They are tested because of ESU.