Error.ps1

# sample configuration
configuration Hoge
{
    Node localhost
    {
        File Hoge
        {
            Ensure = $Node.Ensure
            DestinationPath = $Node.DestinationPath
            Type = 'Directory'
        }
        
        User Hoge
        {
            UserName = "Hoge"
            Password = $Node.Credential
            Ensure = 'Present'
            Disabled = $false
        }
    }
}

$cred = (Get-Credential)

# create configurationData
$configurationData = New-Object 'System.Collections.Generic.Dictionary[string, hashtable[]]'
$a = New-Object System.Collections.Hashtable
$a.Add("Credential",$cred)
$a.Add("NodeName", "*")
$a.Add("PSDSCAllowPlainTextPassword", $true)
$a.Add("Ensure", "Present")
$a.Add("DestinationPath","c:\fuga")

$b = New-Object System.Collections.Hashtable
$b.Add("NodeName","localhost")

$configurationData["AllNodes"] = @($a, $b)

Hoge -ConfigurationData $configurationData
Start-DscConfiguration -Wait -Force -Verbose Hoge

Fix.ps1

class HashtableComparer : System.Collections.IEqualityComparer
{
    [bool] Equals([object]$obj, [object]$obj2)
    {
        return $obj -eq $obj2;
    }

    [int] GetHashCode([object]$obj)
    {
        return $obj.ToString().ToLower().GetHashCode();
    }
}
$comparer = New-Object HashtableComparer;

# sample configuration
configuration Hoge
{
    Node localhost
    {
        File Hoge
        {
            Ensure = $Node.Ensure
            DestinationPath = $Node.DestinationPath
            Type = 'Directory'
        }
        
        User Hoge
        {
            UserName = "Hoge"
            Password = $Node.Credential
            Ensure = 'Present'
            Disabled = $false
        }
    }
}

$cred = (Get-Credential)

# create configurationData
$configurationData = New-Object 'System.Collections.Generic.Dictionary[string, hashtable[]]'
$a = New-Object System.Collections.Hashtable ($comparer)
$a.Add("Credential",$cred)
$a.Add("NodeName", "*")
$a.Add("PSDSCAllowPlainTextPassword", $true)
$a.Add("Ensure", "Present")
$a.Add("DestinationPath","c:\fuga")

$b = New-Object System.Collections.Hashtable ($comparer)
$b.Add("NodeName","localhost")

$configurationData["AllNodes"] = @($a, $b)

Hoge -ConfigurationData $configurationData
Start-DscConfiguration -Wait -Force -Verbose Hoge

Success.ps1

# sample configuration
configuration Hoge
{
    Node localhost
    {
        File Hoge
        {
            Ensure = $Node.Ensure
            DestinationPath = $Node.DestinationPath
            Type = 'Directory'
        }
        
        User Hoge
        {
            UserName = "Hoge"
            Password = $Node.Credential
            Ensure = 'Present'
            Disabled = $false
        }
    }
}

$cred = (Get-Credential)

# create configurationData
$configurationData = New-Object 'System.Collections.Generic.Dictionary[string, hashtable[]]'
$a = @{}
$a.Add("Credential",$cred)
$a.Add("NodeName", "*")
$a.Add("PSDSCAllowPlainTextPassword", $true)
$a.Add("Ensure", "Present")
$a.Add("DestinationPath","c:\fuga")

$b = @{}
$b.Add("NodeName","localhost")

$configurationData["AllNodes"] = @($a, $b)

Hoge -ConfigurationData $configurationData
Start-DscConfiguration -Wait -Force -Verbose Hoge

Error Message

ConvertTo-MOFInstance : System.InvalidOperationException error processing property 'Password' OF TYPE 'User': Converting and storing encrypted passwords as plain text is not recommended. For more information on securing credentials in MOF file, please 
refer to MSDN blog: http://go.microsoft.com/fwlink/?LinkId=393729
At line:13 char:9
+   User
At line:322 char:16
+     $aliasId = ConvertTo-MOFInstance $keywordName $canonicalizedValue
+                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (:) [Write-Error], InvalidOperationException
    + FullyQualifiedErrorId : FailToProcessProperty,ConvertTo-MOFInstance
WARNING: The configuration 'Hoge' is loading one or more built-in resources without explicitly importing associated modules. Add Import-DscResource –ModuleName 'PSDesiredStateConfiguration' to your configuration to avoid this message.
Errors occurred while processing configuration 'Hoge'.
At C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules\PSDesiredStateConfiguration\PSDesiredStateConfiguration.psm1:3705 char:5
+     throw $ErrorRecord
+     ~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (Hoge:String) [], InvalidOperationException
    + FullyQualifiedErrorId : FailToProcessConfiguration