Q:

Matching Double String, how do I only match with 1 result? 

I'm able to match the string I need for regex but it is matching twice.  
https://regex101.com/r/KmgGwS/7
if ( $_.PSPath -match ("(? <=\::)(.*?)(?=\\)+")) {
  $matches. Values
}

For example, the input string is something like:

'Microsoft. PowerShell. Security\Certificate::CurrentUser\Root\A43489159A520F0D93D032CCAF37E7FE20A8B419'

It expect it to get:

CurrentUser

With the current code, it gets that string twice: 

CurrentUser
CurrentUser

A:

What you're seeing is the match value and the
group 1 value.  Both of which contain the same thing.   
If you want to see only a single value, remove the capture group.   
 (? <= :: )
 .*?  
 (? = \\ )

Or, like this (? <=::).*?(?=\\)

