Exchange 2010 Installation Fails with Error "Provisioning layer initialization failed"

For a customer with an older environment, needed to re-build a DAG member and ran into this issue. Upon installation of the management tools, even with a fresh SP3 download, the install would error out. The guts of the error messages were this:

[04/24/2018 22:21:56.0372] [2] [ERROR] Provisioning layer initialization failed: '"Scripting Agent initialization failed: "File is not found: 'C:\Program Files\Microsoft\Exchange Server\V14\Bin\CmdletExtensionAgents\ScriptingAgentConfig.xml'.""'
[04/24/2018 22:21:56.0372] [2] [ERROR] "Scripting Agent initialization failed: "File is not found: 'C:\Program Files\Microsoft\Exchange Server\V14\Bin\CmdletExtensionAgents\ScriptingAgentConfig.xml'.""
[04/24/2018 22:21:56.0372] [2] [ERROR] "File is not found: 'C:\Program Files\Microsoft\Exchange Server\V14\Bin\CmdletExtensionAgents\ScriptingAgentConfig.xml'."
[04/24/2018 22:21:56.0388] [2] [ERROR] Provisioning layer initialization failed: '"Scripting Agent initialization failed: "File is not found: 'C:\Program Files\Microsoft\Exchange Server\V14\Bin\CmdletExtensionAgents\ScriptingAgentConfig.xml'.""'
[04/24/2018 22:21:56.0388] [2] [ERROR] "Scripting Agent initialization failed: "File is not found: 'C:\Program Files\Microsoft\Exchange Server\V14\Bin\CmdletExtensionAgents\ScriptingAgentConfig.xml'.""
[04/24/2018 22:21:56.0388] [2] [ERROR] "File is not found: 'C:\Program Files\Microsoft\Exchange Server\V14\Bin\CmdletExtensionAgents\ScriptingAgentConfig.xml'."

Turns out, this is related to the PowerShell cmdlet Extension called Scripting Agent, which is enabled by default. Many posts online say you can just go to the path listed above and rename the .sample file to fix it, but that doesn't actually fix the management tools. In actuality, you need to disable the agent, run the install, then (if desired) re-enable the agent.

1. Open a the EMS (Exchange Management Shell) on another exchange server in the org and run:
   

   Disable-CmdletExtensionAgent "Scripting Agent"

2. Fully install Exchange
3. Copy C:\Program Files\Microsoft\Exchange Server\V14\bin\CmdletExtensionAgents\ScriptingAgentConfig.xml from another exchange server to the same path on the new server
4. Re-enable the agent:
   

   Enable-CmdletExtensionAgent "Scripting Agent"

I suppose not much Microsoft could do to work around this without releasing a new service pack, but still frustrating.