Trouble with [datetime]::parseexact - powershell

Question

I know I must be missing something simple, but I've stared at it for a while and can't seem to see it.
I have the following powershell code
.".\Get-FileMetaDataReturnObject.ps1"
$BaseDirectory = "C:\Users\me\Desktop\Photo Test"
$Folders = get-childitem -path $BaseDirectory -Directory
foreach ($folder in $folders)
{
Write-Host "Folder name:$($folder.Name)"
$picture = Get-ChildItem -Path "$BaseDirectory\$($folder.Name)\"
$picMetaData = Get-FileMetaData -folder "$BaseDirectory\$($folder.Name)\"
$picDate = $picMetaData | Select 'Date Taken'
$picDateTaken = $picDate[0].'Date taken'
Write-Host $picDateTaken
$dateTime = [datetime]::parseexact($picDateTaken, "M/d/yyyy h:mm tt", [System.Globalization.CultureInfo]::InvariantCulture)
$dateStr = $dateTime.ToString('yyyy-MM-dd')
Write-Host $dateStr
}
When I run it I get the following error
Folder name:Deruta - Umbria, September 4, 2012
‎9/‎4/‎2012 ‏‎4:12 PM
Exception calling "ParseExact" with "3" argument(s): "String was not recognized as a valid DateTime."
At C:\Users\me\Desktop\Picture Folder Rename\PhotoFolderRename.ps1:18 char:5
+ $dateTime = [datetime]::parseexact($picDateTaken, "M/d/yyyy h:mm ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [], MethodInvocationException
+ FullyQualifiedErrorId : FormatException
The meta data script is found here
I'm really not sure what I've screwed up with the date time parsing, so any help would be appreciated.

Answer 1

Comparing "9/‎4/‎2012 ‏‎4:12 PM".Length (20) with "9/4/2012 4:12 PM".Length (16) shows us something fishy is going on, and indeed this string is not what it appears to be; there are U+200E LEFT-TO-RIGHT MARK and U+200F RIGHT-TO-LEFT MARK control characters in there, which are invisible (or not, depending on your console settings). Replacing these out will make the string parseable:
$picDateTaken = $picDateTaken -replace "\u200e|\u200f", ""
Replacing control characters in general would be more involved, and I'm not sure if there isn't a better/more general way to get the metadata in an invariant format, but as long as you know exactly what you're dealing with this is good enough.