Exchange ECP and OWA error out after updating to CU 23


After upgrading Exchange to CU23 ECP and OWA no longer work.  After logging in to the splash screen Owa was throwing a 500 error.  ECP was showing “Could not load file or assembly ‘Microsoft.Exchange.Common, Version= …”




Open IIS Manager -> Expand Sites-> Exchange Back End

Click ECP.  Open the Application Settings in the middle column

Please check whether the value for “BinSearchFolders” is changed to an invalid value or %ExchangeInstall% or %ExchangeInstallPath%

For example, if your exchange file installation is on default location, please change it to:

C:\Program Files\Microsoft\Exchange Server\V15\bin;C:\Program Files\Microsoft\Exchange Server\V15\bin\CmdletExtensionAgents;C:\Program Files\Microsoft\Exchange Server\V15\ClientAccess\Owa\bin

Run IISRESET from command prompt

If the ECP is still showing an error. Open Web.config file for OWA in the default path C:\Program Files\Microsoft\Exchange Server\V15\ClientAccess\Owa. If there is any %ExchangeInstallDir% in the web.config content, replace all of them with C:\Program Files\Microsoft\Exchange Server\V15\

Check the web.config file for ECP in Exchange back end and confirm if there is any %ExchangeInstallDir% in the web.config content. If that is the case, please replace all of %ExchangeInstallPath% to c:\programfiles\Microsoft\Exchange Server\V15\Bin

If after all steps above the ECP still showing an error, run UpdateCas.PS1 under “bin” folder on the exchange directory installation