Accessing Mapped Network Drive Fails In Scheduled Task - powershell

Question

I have the following powershell script which checks a drive to see if it is low on space, and if so stops sabnzbd downloads and sends me an email:
$disk = Get-WmiObject Win32_LogicalDisk -Filter "DeviceID='B:'" | Select-Object FreeSpace
$gb =$disk.FreeSpace /1073741824
if($gb -lt 3)
{
$wc = New-Object system.Net.WebClient;
$smsResult = $wc.downloadString("http://localhost:8080/sabnzbd/api?mode=pause&apikey=XXXXXXX")
$EmailFrom = "XXXXXXX"
$EmailTo = "XXXXXXX"
$Subject = "NAS out of space <eom>"
$Body = ""
$SMTPServer = "smtp.gmail.com"
$SMTPClient = New-Object Net.Mail.SmtpClient($SmtpServer, 587)
$SMTPClient.EnableSsl = $true
$SMTPClient.Credentials = New-Object System.Net.NetworkCredential("XXXXXXX", "XXXXXXX");
$SMTPClient.Send($EmailFrom, $EmailTo, $Subject, $Body)
}
This works perfectly when running in powershell through the console or ISE, but when I setup a scheduled task the WMI query returns the drive size as 0. I do not get any errors and task scheduler says the task completed successfully. I run the task with elevated privileges as my administrator account. Have also tried to run as SYSTEM without any luck. I have seen other people ask similar questions a long time ago, but it does not seem like they got any answers.

Answer 1

Working off of andyb's comment I was able to fix this by mapping and unmapping the drive explicitly so that Powershell can use it.
$net = new-object -ComObject WScript.Network
$net.MapNetworkDrive("K:", "\\192.0.0.0\NAS", $false, "192.0.0.0\NASAdmin", "xxxxxx")
$disk = Get-WmiObject Win32_LogicalDisk -Filter "DeviceID='K:'" | Select-Object FreeSpace
$gb =$disk.FreeSpace /1073741824
$gb>E:\test.txt
if($gb -lt 3)
{
$wc = New-Object system.Net.WebClient;
$smsResult = $wc.downloadString("http://localhost:8080/sabnzbd/api?mode=pause&apikey=xxxxxx")
$EmailFrom = "xxxxxx"
$EmailTo = "xxxxxx"
$Subject = "NAS out of space <eom>"
$Body = ""
$SMTPServer = "smtp.gmail.com"
$SMTPClient = New-Object Net.Mail.SmtpClient($SmtpServer, 587)
$SMTPClient.EnableSsl = $true
$SMTPClient.Credentials = New-Object System.Net.NetworkCredential("xxxxxx", "xxxxxx");
$SMTPClient.Send($EmailFrom, $EmailTo, $Subject, $Body)
}
Start-Sleep 5
$net.RemoveNetworkDrive("K:");