ExchangeOnline sync error Could not load type 'Microsoft.IdentityModel.Abstractions.ITelemetryClient'

Hello Henrik

I ran into the same issue in my environment version 9.1.1, which led me to your post.

I was getting the same error when trying to execute PowerShell commands via processes using the PowerShell component Net4.

ErrorMessages	(2025-03-17 13:26:05.750) [Progress] Preparing modules for first use.
[System.Management.Automation.RuntimeException] Could not load type 'Microsoft.IdentityModel.Abstractions.ITelemetryClient' from assembly 'Microsoft.IdentityModel.Abstractions, Version=6.19.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'.
[System.TypeLoadException] Could not load type 'Microsoft.IdentityModel.Abstractions.ITelemetryClient' from assembly 'Microsoft.IdentityModel.Abstractions, Version=6.19.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'.
   at StdioProcessor.StdioProcessor._Execute(Job job)
   at VI.Jobservice.JobComponents.PowershellComponentNet4.Activate(String task)
   at VI.Jobservice.JobComponents.PoshBaseTask.Execute()
   at VI.Base.PowerShell.Runner.RunspaceUtils.Run(Runspace target, IPoshExecutionItem item, Int32 maxDeserDepth)
   at System.Management.Automation.Runspaces.PipelineBase.Invoke(IEnumerable input)
   ---- Start of Inner Exception ----
   at Microsoft.Exchange.Management.ExoPowershellSnapin.GetConnectionContext.ProcessRecord()
   at Microsoft.Exchange.Management.AdminApiProvider.Authentication.TokenProviderFactory.CreateTokenProvider(TokenProviderContext context, ICmdletLogger cmdletLogger)
   at Microsoft.Exchange.Management.AdminApiProvider.Authentication.MSALTokenProvider..ctor(TokenProviderContext tokenProviderContext, ICmdletLogger cmdletLogger)
   at Microsoft.Exchange.Management.AdminApiProvider.Authentication.MSALTokenProvider.GetConfidentialClientInstance()
   at Microsoft.Identity.Client.ConfidentialClientApplicationBuilder.Create(String clientId)
   at Microsoft.Identity.Client.ApplicationConfiguration..ctor(MsalClientType applicationType)

 Here's what worked for me:

1. Installed ExchangeOnlineManagement v3.7.1 for all users.

2. Went to: C:\Program Files\WindowsPowerShell\Modules\ExchangeOnlineManagement\3.7.1\netFramework

3. Found and copied Microsoft.IdentityModel.Abstractions.dll from that folder.

4. Navigated to the One Identity installation folder (for me, it was: C:\Program Files\One Identity\One Identity Manager)

5. Found the existing Microsoft.IdentityModel.Abstractions.dll and made a backup.

6. Replaced it with the newer Microsoft.IdentityModel.Abstractions.dll (from ExchangeOnlineManagement v3.7.1).

I am not sure if it's correct but it solved the issue for me, I hope it helps you.