JazDotKiwi650 I reached out to PRTG support and they said several customers have already reported this remote powershell issue. Their dev team is working on a hotfix/update to remediate due to the changes in Microsoft code. Hopefully its a quick turnaround and fixed soon and not have to wait for a Microsoft update. Looking like they changed it to fix the vulnerability, unless they accidentally broke it, which then we'll have to wait for an update or some combination.

Good luck with your other app.

We are using PRTG to monitor our Exchange Servers and it can't do remote powershell with remote exchange management shell with the Exchange server after I installed the April Security update.

I upgraded from CU18 to CU20 successfully (cmd prompt elevated as administrator), monitoring was still fine at that point. Like I have done numerous times for both CUs and security updates. Then when I applied April security update for CU20 (cmd prompt elevated as admin), powershell is failing with this message below:

The sensor was able to connect to the device using Remote PowerShell but could not retrieve access to Remote Exchange Management Shell. Ensure that remote management is enabled on the Exchange Server and the user has sufficient rights. See https://kb.paessler.com/en/topic/54353 for details. The syntax is not supported by this runspace. This can occur if the runspace is in no-language mode.

It has the appropriate permissions, nothing has changed there, confirmed its still good. It was working fine before the security update. I got this same behavior on both my DR exchange servers, so not proceeding with my production ones until I know what's going on or hear from someone at Microsoft. Did the security update change something with remote exchange management shell and that was the vulnerability fix? Perhaps PRTG vendor needs to supply and update and adjust their sensor accordingly if by Microsoft design this was changed?

I've validated all the services automatic are running, test-servicehealth, test-replicationhealth, virtual powershell directory, exchange management shell works fine on server, get-mailboxdatabasecopystatus, reviewed application logs and no issues.

Hope you can help Nino_Bilic The_Exchange_Team or someone?

niels haaijer - Yes, apply to Edge servers too

SA - There is a specifici FAQ about Hybrid in the post; but if you are running hybrid, you are running Exchange on-premises. If you are on CU23 for Exchange 2013, you simply need to either install the April update from Microsoft Update or if you are downloading it, you MUST install the update from the elevated CMD prompt. The KB article tells you what to do (in known issues) and download instructions tell you also. It should be ~30 minutes.

Vinch_BE - yes, best is to reboot after done!

FreakyNL - unknown at this time; we do have a repro of this and engineering is looking into it. Sorry, no better answer right now!

mhincapie anthonytenherkel JazDotKiwi650 Googol GregS410 - at this time, I do not have an answer for you; I think based on error samples you have provided (thank you!), we have a good idea where to look; engineering has been engaged on this. 3rd party monitoring is something that we cannot test for in our test passes but still - if we have deliberately changed something here, we need to document it for sure. Consider this under investigation.

Thank you for keeping up the update history for the OP.

Also Kudos for the very comprehensive guidance and references how to check and apply patches correctly.

The_Exchange_Team 

We’re running Exchange 2016 CU19 and are planning to upgrade to CU20 in several weeks. Do we need to reapply this patch after installing CU20 if we patch CU19?

alabkrishnan - it is SUPER important that you install from elevated CMD prompt; I really want to make sure that this was done (it is unclear what the error was) - I just helped someone on Reddit with the same problem. This is exactly the symptom and resolution: Repair failed installations of Exchange Cumulative and Security updates - Exchange | Microsoft Docs

Can someone on the Exchange team PLEASE tell us why the "run from admin" hasn't either been corrected or coded to be detected yet?  Absurd. . .

alabkrishnan hey, you got a $ or other special chars in your username?

Copied my admin account to one without $ in the names - problems be gone.

luke_q7 - the installation that you have should be a 'regular' Exchange installation; it is simply an on-premises install and you should update it. At this point, we do not have any plans to release fixes for older CUs.

March was the ONLY time that we have done such a thing (and we release security updates often, not every single month but often) - and it was because of active exploits by a particular actor (it was a very unique situation). Released updates for older CUs were not full updates either; those updates only addressed 4 March vulnerabilities. They were not 'cumulative' security updates like we release usually. Please update... Exchange Update Wizard will give you the steps that you need to follow.

Hi I've installed the patch to an Exchange 2016 server, the installation seemed to go fine and Exchange appears to is operating normally post reboot, however i've got an issue with a couple of 3rd party applications that connect to exchange via remote powershell and they are both broken.

One is our monitoring application called PRTG, and appears to be the same issue as mentioned by Googol.

I've enabled sensor debug logging and can see the following error message in the PRTG sensor logs.

2021-04-14 20:03:32,457 [DEBUG] - Running script: 'Get-ExchangeServer'
2021-04-14 20:03:32,490 [ERROR] - Error in RunRequest Get-ExchangeServer
2021-04-14 20:03:32,490 [ERROR] - Exception occured
System.Management.Automation.RemoteException: The syntax is not supported by this runspace. This can occur if the runspace is in no-language mode.
at System.Management.Automation.Runspaces.AsyncResult.EndInvoke()
at System.Management.Automation.PowerShell.CoreInvokeRemoteHelper[TInput,TOutput](PSDataCollection`1 input, PSDataCollection`1 output, PSInvocationSettings settings)
at System.Management.Automation.PowerShell.CoreInvoke[TInput,TOutput](PSDataCollection`1 input, PSDataCollection`1 output, PSInvocationSettings settings)
at System.Management.Automation.PowerShell.CoreInvoke[TOutput](IEnumerable input, PSDataCollection`1 output, PSInvocationSettings settings)
at System.Management.Automation.PowerShell.Invoke(IEnumerable input, PSInvocationSettings settings)
at System.Management.Automation.RemotePipeline.Invoke(IEnumerable input)
at ExchangeSensorPS.ExchangeSensorProgram.RunRequest(String script)
at ExchangeSensorPS.ExchangeSensorProgram.GetExchangeProductVersion(Collection`1 result)
at ExchangeSensorPS.ExchangeSensorProgram.Main(String[] args)

Our other application that is also broken is an in house tool we use for Exchange admin tasks is producing a similar error message, the keywords are "System.Management.Automation.RemoteException: The syntax is not supported by this runspace. This can occur if the runspace is in no-language mode."

Any ideas?