Powershell script cannot access a file when run as a Scheduled Task

Question

My Powershell (2.0) script has the following code snippet:

$fileName = "c:\reports\1.xlsx"
$xl = new-object -comobject excel.application
$xlFormat = [Microsoft.Office.Interop.excel.XlFileFormat]::xlWorkbookDefault
$xl.displayalerts = $false
$workbook = $xl.workbooks.open($fileName)
#Code to manipulate a worksheet
$workbook.SaveAs($fileName, $xlformat)
$xl.quit()
$error | out-file c:\reports\error.txt

I can run this script in the Powershell command prompt with no issues. The spreadsheet gets updated, and error.txt is empty. However, when I run it as a task in Task Scheduler, I get errors with the first line.

Exception calling "Open" with "1" argument(s): "Microsoft Office Excel cannot access the file 'C:\reports\1.xlsx'. There are several possible reasons: The file name or path does not exist. The file is being used by another program. The workbook you are trying to save has the same name as a currently open workbook.

I run the task with the same credentials I use to run the script in the Powershell command prompt. When I run the script manually, it can open, update, and save the spreadsheet with no issues. When I run it in Task Scheduler, it can't access the spreadsheet.

The file in question is readable/writeable for all users. I've verified I can open the file in Excel with the same credentials. If I make a new spreadsheet and put its name in as the $filename, I get the same results. I've verified that there are no instances of Excel.exe in Task Manager.

Oddly, if I use get-content, I don't have any problems. Also, if I make a new spreadsheet, I don't have any problem.

$fileName = "c:\reports\1.xlsx"
$xl = get-content $spreadsheet
$xl = new-object -comobject excel.application
$xlFormat = [Microsoft.Office.Interop.excel.XlFileFormat]::xlWorkbookDefault
$xl.displayalerts = $false
# Commented out $workbook = $xl.workbooks.open($fileName)
$workbook = $xl.workbooks.add()
#Code to manipulate a worksheet
$workbook.SaveAs($fileName, $xlformat)
$xl.quit()
$error | out-file c:\reports\error.txt

That works fine. So Get-ChildItem can open the file with no issue. ComObject can open the file if I run it manually, but not if it's run as task.

I'm at a loss. Any ideas?

Answer 1

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 )

Answer 2

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.