Error during upgrade CU5 to CU18 / Exchange 2016

Question

We did already two times the update from cu5 to cu18 (exchange 2016). We prepared everything as it should and that is not the issue. I know cu5 to cu18 is a lot of cu between but we want to upgrade this way.
After executing setup /mode:upgrade /Iacceptexchangeserverlicenseterms it went well until it comes to upgrade the case mailbox service. It goes to 100%.

It stopts with this error (part of but I think the most important part).
First it tells us that the ECP already exists and then it tells us that it cannot be found? Very confusion.

part of the error log.
[11/21/2020 12:48:21.0776] [2] [ERROR] The virtual directory 'ecp' already exists under 'ex02.Ixx.Mxx.ixx/Exchange Back End'.
Parameter name: VirtualDirectoryName
[11/21/2020 12:48:21.0791] [2] Ending processing new-EcpVirtualDirectory
[11/21/2020 12:48:21.0791] [2] Active Directory session settings for 'Set-EcpVirtualDirectory' are: View Entire Forest: 'True', Configuration Domain Controller: 'AD03.Ixx.Mxx.ixx', Preferred Global Catalog: 'AD03.Ixx.Mxx.ixx', Preferred Domain Controllers: '{ AD03.Ixx.Mxx.ixx }'
[11/21/2020 12:48:21.0791] [2] User specified parameters: -Identity:'EX02\ECP (Exchange Back End)' -FormsAuthentication:'False' -WindowsAuthentication:'True'
[11/21/2020 12:48:21.0791] [2] Beginning processing set-EcpVirtualdirectory
[11/21/2020 12:48:21.0791] [2] Searching objects "EX02\ECP (Exchange Back End)" of type "ADEcpVirtualDirectory" under the root "$null".
[11/21/2020 12:48:21.0791] [2] Previous operation run on domain controller 'AD03.Ixx.Mxx.ixx'.
[11/21/2020 12:48:21.0791] [2] [ERROR] The operation couldn't be performed because object 'SRVINFEX02\ECP (Exchange Back End)' couldn't be found on 'AD03.Ixx.Mxx.ixx'.

I hope there is someone amongst all of you that know this issue and can lead us to a possible solution.
Many thanks in advance.

Best regards
Kurt

Answer 1

A short end.

After creating the keys for the ecp in AD we could try the update again.
Set-ADServerSettings -ViewEntireForest $true
Get-Mailbox -Arbitration
f:\Setup.exe /IAcceptExchangeServerLicenseTerms /Mode:Upgrade

But then another error appeared: cannot find exchangeserver.msi.
I didn't know what to do and so I tried running the setup with the file itself.
It went through all the 17 steps and all went well.

I could restart and everything was ok: I saw the cu18 everywhere I looked.

So this case can be closed.

Another little issue is that some users get a popup while opening their Outlook and they have to logon with their own credentiasl as the account they use to logon into their windows/citrix profile. but it is not for every account and once filled in it stays until another logoff/logon. But maybe it is better to make a new Q&A for that.

Answer 2

For all who have the same problem, just recreate the ecp (Default Website) using PowerShell

Remove-EcpVirtualDirectory -Identity “ex2016\ecp (Default Web Site)”

New-EcpVirtualDirectory  -InternalUrl “https://mail.contoso.local/ecp” -ExternalUrl  “https://mail.contoso.local/ecp”

, and delete the key for the ecp (Exchange back end)with IIS Metabase explorer.

Then start the setup with administrator cmd and it will recreate the key in the database and your problem should be fixed. You'll be able to see the entry in the ASDIEDIT as well.