jonathanwoods

@jonathanwoods - This issue is resolved in the next upcoming release 2026.3.0 👍

@DataTraveler

Thank you DataTraveler and @Adam Driscoll .

Hi Adam, thanks for the response.

See below for what appears to be a couple of relevant section from the system log:

2026-08-17 13:00:00.325 +01:00 [INF][PowerShellUniversal.Automation.ExecutionService] Job 232 started.
2026-08-17 13:00:02.302 +01:00 [INF][PowerShellUniversal.Automation.RemotingExecutionService] Configuring runspace for environment PowerShell 7 with version 2026.2.4
2026-08-17 13:00:03.934 +01:00 [ERR][PowerShellUniversal.Automation.RemotingExecutionService] Job failed. Cannot convert '' to the type 'System.Collections.Generic.ICollection`1[System.String]' required by parameter 'Collection'. Specified method is not supported.    at System.Management.Automation.Runspaces.AsyncResult.EndInvoke()
   at System.Management.Automation.PowerShell.EndInvoke(IAsyncResult asyncResult)
   at UniversalAutomation.Host.JobService.ExecuteScript(ExecuteScriptRequest request) in D:\a\powershell-universal\powershell-universal\src\Host\JobService.cs:line 274
2026-08-17 13:00:03.944 +01:00 [ERR][PowerShellUniversal.Automation.RemotingExecutionService] Job failed. Access is denied.    at System.Diagnostics.Process.Kill()
   at PowerShellUniversal.Automation.PSHostClientSessionTransportMgr.CleanupConnection() in D:\a\powershell-universal\powershell-universal\src\PowerShellUniversal.Automation\PSHostSession.cs:line 167
   at PowerShellUniversal.Automation.PSHostClientSessionTransportMgr.Dispose(Boolean isDisposing) in D:\a\powershell-universal\powershell-universal\src\PowerShellUniversal.Automation\PSHostSession.cs:line 157
   at System.Management.Automation.Remoting.BaseTransportManager.Dispose()
   at System.Management.Automation.Remoting.ClientRemoteSessionDSHandlerImpl.Dispose()
   at System.Management.Automation.Remoting.ClientRemoteSessionImpl.Dispose(Boolean disposing)
   at System.Management.Automation.Remoting.ClientRemoteSessionImpl.Dispose()
   at System.Management.Automation.Internal.ClientRunspacePoolDataStructureHandler.Dispose(Boolean disposing)
   at System.Management.Automation.Runspaces.Internal.RemoteRunspacePoolInternal.Dispose(Boolean disposing)
   at System.Management.Automation.Runspaces.Internal.RunspacePoolInternal.Dispose()
   at System.Management.Automation.Runspaces.RunspacePool.Dispose()
   at System.Management.Automation.RemoteRunspace.Dispose(Boolean disposing)
   at System.Management.Automation.Runspaces.Runspace.Dispose()
   at UniversalAutomation.Host.JobService.ExecuteScript(ExecuteScriptRequest request) in D:\a\powershell-universal\powershell-universal\src\Host\JobService.cs:line 343
2026-08-17 13:00:03.956 +01:00 [INF][PowerShellUniversal.Automation.ExecutionService] Job 232 completed with status Failed.

2026-08-17 15:00:03.991 +01:00 [INF][PowerShellUniversal.Automation.ExecutionService] Job 239 started.
2026-08-17 15:00:05.201 +01:00 [INF][PowerShellUniversal.Automation.RemotingExecutionService] Configuring runspace for environment PowerShell 7 with version 2026.2.4
2026-08-17 15:00:06.968 +01:00 [ERR][PowerShellUniversal.Automation.RemotingExecutionService] Job failed. Cannot convert '' to the type 'System.Collections.Generic.ICollection`1[System.String]' required by parameter 'Collection'. Specified method is not supported.    at System.Management.Automation.Runspaces.AsyncResult.EndInvoke()
   at System.Management.Automation.PowerShell.EndInvoke(IAsyncResult asyncResult)
   at UniversalAutomation.Host.JobService.ExecuteScript(ExecuteScriptRequest request) in D:\a\powershell-universal\powershell-universal\src\Host\JobService.cs:line 274
2026-08-17 15:00:06.970 +01:00 [ERR][PowerShellUniversal.Automation.RemotingExecutionService] Job failed. The handle is invalid.    at System.Diagnostics.Process.Kill()
   at PowerShellUniversal.Automation.PSHostClientSessionTransportMgr.CleanupConnection() in D:\a\powershell-universal\powershell-universal\src\PowerShellUniversal.Automation\PSHostSession.cs:line 167
   at PowerShellUniversal.Automation.PSHostClientSessionTransportMgr.Dispose(Boolean isDisposing) in D:\a\powershell-universal\powershell-universal\src\PowerShellUniversal.Automation\PSHostSession.cs:line 157
   at System.Management.Automation.Remoting.BaseTransportManager.Dispose()
   at System.Management.Automation.Remoting.ClientRemoteSessionDSHandlerImpl.Dispose()
   at System.Management.Automation.Remoting.ClientRemoteSessionImpl.Dispose(Boolean disposing)
   at System.Management.Automation.Remoting.ClientRemoteSessionImpl.Dispose()
   at System.Management.Automation.Internal.ClientRunspacePoolDataStructureHandler.Dispose(Boolean disposing)
   at System.Management.Automation.Runspaces.Internal.RemoteRunspacePoolInternal.Dispose(Boolean disposing)
   at System.Management.Automation.Runspaces.Internal.RunspacePoolInternal.Dispose()
   at System.Management.Automation.Runspaces.RunspacePool.Dispose()
   at System.Management.Automation.RemoteRunspace.Dispose(Boolean disposing)
   at System.Management.Automation.Runspaces.Runspace.Dispose()
   at UniversalAutomation.Host.JobService.ExecuteScript(ExecuteScriptRequest request) in D:\a\powershell-universal\powershell-universal\src\Host\JobService.cs:line 343
2026-08-17 15:00:07.026 +01:00 [INF][PowerShellUniversal.Automation.ExecutionService] Job 239 completed with status Failed.

We installed using the MSI. The only customization we have done is to add a publicly trusted SSL cert, modifying the appsettings.json file with (obfuscated):

  "Kestrel": {
    "Endpoints": {
      "HTTP": {
        "Url": "http://*:5000"
      },
      "HTTPS": {
        "Url": "https://*:5001",
    "Certificate":{
       "Path": "C:\\cert\\psuniversal.domain.com\\psuniversal.domain.com.pfx",
       "Password": "password"
    }
      }
    }
  },

Appreciate any help you can offer.

Thanks

Hi,

We recently installed PSU, and when testing scheduled scripts they are all failing immediately with the following error:

Cannot convert '' to the type 'System.Collections.Generic.ICollection`1[System.String]' required by parameter 'Collection'. Specified method is not supported.

This happens with all scripts tested so far, including all execution environments (PS 5.1, 7, and integrated).

Any help would be much appreciated.

Thanks