Powershell script cannot access a file when run as a Scheduled Task
I had to set my Scheduled Task to run 'only when user is logged on' (logged on to server as the service account that runs task then disconnect session) as it seems to be a limitation with the Task Scheduler and Excel. It's a pretty lame workaround but it works.
The solutions above didn't work in my SCSM 2012 Scorch environment, instead I used PSExcel (https://github.com/RamblingCookieMonster/PSExcel) which has no dependency on having Excel installed or the ComObject.
I think you've hit a bug in Excel:
You have to create a folder (or two on a 64bit-windows):
(32Bit, always)
C:\Windows\System32\config\systemprofile\Desktop
(64Bit)
C:\Windows\SysWOW64\config\systemprofile\Desktop
I have had the same problem and this was the only solution i have found.
From TechNet Forums (via PowerShell and Excel Issue when Automating )
To extend what @TessellatingHeckler provided, you can run the following commands in Powershell(As Admin/Elevated) to create the folders before opening excel, in my script this fixed the issue:
New-Item -ItemType Directory -Force -Path C:\Windows\System32\config\systemprofile\Desktop
if ([Environment]::Is64BitProcess -ne [Environment]::Is64BitOperatingSystem)
{
New-Item -ItemType Directory -Force -Path C:\Windows\SysWOW64\config\systemprofile\Desktop
}