I only found one other instance of this in the forum and it went away on it's own for them somehow. I confirmed the Microsoft.Management.Infrastructure.CimCmdlets.dll PublicKeyToken in C:\Program Files\Otter\Service matched the error in case there was a version mismatch. I've reinstalled repreatedly, tried old versions, restarted, nothing is helping. I can get a newer version from nuget but not sure that would work.

Logged: 10/13/2023 3:09:32 PM
 Level: Error
 Category: ServerCheckerRunner
 Message: Error scanning PowerShell agent: Could not load file or assembly 'Microsoft.Management.Infrastructure, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'. The system cannot find the file specified.
 Details: System.IO.FileNotFoundException: Could not load file or assembly 'Microsoft.Management.Infrastructure, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'. The system cannot find the file specified.
File name: 'Microsoft.Management.Infrastructure, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'
at System.Management.Automation.CimClassDeserializationCache`1..ctor()
at System.Management.Automation.DeserializationContext..ctor(DeserializationOptions options, PSRemotingCryptoHelper cryptoHelper)
at System.Management.Automation.Remoting.Fragmentor..ctor(Int32 fragmentSize, PSRemotingCryptoHelper cryptoHelper)
at System.Management.Automation.Remoting.BaseTransportManager..ctor(PSRemotingCryptoHelper cryptoHelper)
at System.Management.Automation.Remoting.Client.BaseClientTransportManager..ctor(Guid runspaceId, PSRemotingCryptoHelper cryptoHelper)
at System.Management.Automation.Remoting.Client.BaseClientSessionTransportManager..ctor(Guid runspaceId, PSRemotingCryptoHelper cryptoHelper)
at System.Management.Automation.Remoting.Client.WSManClientSessionTransportManager..ctor(Guid runspacePoolInstanceId, WSManConnectionInfo connectionInfo, PSRemotingCryptoHelper cryptoHelper, String sessionName)
at System.Management.Automation.Runspaces.WSManConnectionInfo.CreateClientSessionTransportManager(Guid instanceId, String sessionName, PSRemotingCryptoHelper cryptoHelper)
at System.Management.Automation.Remoting.ClientRemoteSessionDSHandlerImpl..ctor(ClientRemoteSession session, PSRemotingCryptoHelper cryptoHelper, RunspaceConnectionInfo connectionInfo, URIDirectionReported uriRedirectionHandler)
at System.Management.Automation.Remoting.ClientRemoteSessionImpl..ctor(RemoteRunspacePoolInternal rsPool, URIDirectionReported uriRedirectionHandler)
at System.Management.Automation.Internal.ClientRunspacePoolDataStructureHandler.CreateClientRemoteSession(RemoteRunspacePoolInternal rsPoolInternal)
at System.Management.Automation.Internal.ClientRunspacePoolDataStructureHandler..ctor(RemoteRunspacePoolInternal clientRunspacePool, TypeTable typeTable)
at System.Management.Automation.Runspaces.Internal.RemoteRunspacePoolInternal.CreateDSHandler(TypeTable typeTable)
at System.Management.Automation.Runspaces.Internal.RemoteRunspacePoolInternal..ctor(Int32 minRunspaces, Int32 maxRunspaces, TypeTable typeTable, PSHost host, PSPrimitiveDictionary applicationArguments, RunspaceConnectionInfo connectionInfo, String name)
at System.Management.Automation.Runspaces.RunspacePool..ctor(Int32 minRunspaces, Int32 maxRunspaces, TypeTable typeTable, PSHost host, PSPrimitiveDictionary applicationArguments, RunspaceConnectionInfo connectionInfo, String name)
at System.Management.Automation.RemoteRunspace..ctor(TypeTable typeTable, RunspaceConnectionInfo connectionInfo, PSHost host, PSPrimitiveDictionary applicationArguments, String name, Int32 id)
at System.Management.Automation.Runspaces.RunspaceFactory.CreateRunspace(RunspaceConnectionInfo connectionInfo, PSHost host, TypeTable typeTable, PSPrimitiveDictionary applicationArguments, String name)
at System.Management.Automation.Runspaces.RunspaceFactory.CreateRunspace(RunspaceConnectionInfo connectionInfo, PSHost host, TypeTable typeTable)
at Inedo.Agents.PowerShell.PowerShellAgentClient.Connect(PowerShellConnectionInfo connectionInfo)
at Inedo.Agents.PowerShell.PowerShellAgentClient.ConnectAsync(PowerShellConnectionInfo connectionInfo)
at Inedo.Otter.Service.Agents.PowerShellAgentConnection.CreateAsync(PowerShellAgent agent, Boolean connect, CancellationToken cancellationToken)
at Inedo.Otter.Extensions.Agents.ConnectingAgent.GetConnectionAsync(CancellationToken cancellationToken)
at Inedo.Otter.Service.TaskRunners.ServerCheckerRunner.<>c__DisplayClass14_0.<<CheckPowerShellAgentAsync>g__internalScan|0>d.MoveNext()