Today, I ran:
Save-RunHistory -File I:\Scripts\_Investigations\_data\RunHistory_2020.08.17.xml
which generated a file of around 15 KB.

Then I ran:
Get-SavedRunHistory -File I:\Scripts\_Investigations\_data\RunHistory_2020.08.17.xml
and got no results.

I had a nose around in the source for RunDetails.cs in miis-client and then ran this:
Get-Content -path I:\Scripts\_Investigations\_data\RunHistory_2020.08.17.xml -First 3
and got these lines:

	<?xml version="1.0" encoding="utf-8"?>
	<execution-histories>
	  <run-details>

I think the issue is in line 108 of RunDetails.cs where it says:

foreach (XmlNode node in d.SelectNodes("/execution-histories/run-history/run-details"))

I'm running the current version of LithnetMiisAutomation:

PS C:\Windows\system32> Get-Module LithnetMiisAutomation | Select-Object -Property Name,Version

Name                  Version
----                  -------
LithnetMiisAutomation 1.0.6960.34402	

and MIM 4.6.34:

PS C:\Windows\system32> (Get-Item "C:\Program Files\Microsoft Forefront Identity Manager\2010\Synchronization Service\Bin\miiserver.exe").VersionInfo | Select-O
bject -Property FileVersion,ProductVersion

FileVersion ProductVersion
----------- --------------
4.6.34.0    4.6.34.0