A: Error: The type initializer for Microsoft.Exchange.Configuration.Tasks.ThrottlingModule`1 threw an exception.
I followed these steps after removing exchange server 2013 using ADSIEdit:
1. First remove [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ExchangeServer]
And then add the following Keys:
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ExchangeServer]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ExchangeServer\v15]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ExchangeServer\v15\FIP-FS]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ExchangeServer\v15\FIP-FS\SQM]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ExchangeServer\v15\Pickup]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ExchangeServer\v15\Search]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ExchangeServer\v15\Search\SystemParameters]
2. Step Two is to Uninstall IIS, restart the the exchange server and then re-run the pre-requisite install command in Windows Powershell on the Exchange Server:
"Install-WindowsFeature AS-HTTP-Activation, Desktop-Experience, NET-Framework-45-Features, RPC-over-HTTP-proxy, RSAT-Clustering, RSAT-Clustering-CmdInterface, Web-Mgmt-Console, WAS-Process-Model, Web-Asp-Net45, Web-Basic-Auth, Web-Client-Auth, Web-Digest-Auth,
Web-Dir-Browsing, Web-Dyn-Compression, Web-Http-Errors, Web-Http-Logging, Web-Http-Redirect, Web-Http-Tracing, Web-ISAPI-Ext, Web-ISAPI-Filter, Web-Lgcy-Mgmt-Console, Web-Metabase, Web-Mgmt-Console, Web-Mgmt-Service, Web-Net-Ext45, Web-Request-Monitor, Web-Server,
Web-Stat-Compression, Web-Static-Content, Web-Windows-Auth, Web-WMI, Windows-Identity-Foundation"
I tried these two steps and it cleared the 'throthlingModule' error for me.