Task Scheduler fails; command line succeeds

geoB · Apr 25, 2026

As I try to teach myself python, I built a script to do a daily update of an Excel spreadsheet. I've not yet stumbled on a workable Task Scheduler configuration.

Scheduler:

Run whether or not logged in: Checked

Highest privileges: Checked

Action: C:\Users\truck\AppData\Local\Programs\Python\Python314\python.exe

Arguments: G:\workspace\apples\temp-forecast.py

Start in: G:\workspace\apples

Python: Script downloads a single sheet Excel file showing 14 days of hourly temperatures plus the time of sunset for the same 14 days. (Codling moths larvae are on the move on apple trees when temperature at sunset is 62° or greater.)

Running the Scheduler at 3 AM or clicking on Run in the Scheduler does not update Excel. Running "C:\Users\truck\AppData\Local\Programs\Python\Python314\python.exe G:\workspace\apples\temp-forecast.py" (sans quotes) at the powershell command line will update Excel. I ran a short version of this in Google that suggested an addendum to the arguments that would create a log.txt but that never worked eithter.

Any idea on how to automate this? Or even how to get an error log?

pepanee · Apr 25, 2026

Check out AI's possible answer. This answer makes you save a certain script into a ps1 file, and suggests what steps to set up in Task Scheduler to run that ps1 file on a daily basis.

Link:

write "C:\Users\truck\AppData\Local\Programs\Python\Python314\python.exe G:\workspace\apples\temp-forecast.py" in a powershell script and set it to run every day in task scheduler - Bing

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Or if you want, go to the Bing search engine, copy/paste the following, and press Search:

write "C:\Users\truck\AppData\Local\Programs\Python\Python314\python.exe G:\workspace\apples\temp-forecast.py" in a powershell script and set it to run every day in task scheduler

garlin · Apr 25, 2026

It sounds like there's user environment problems running it from a scheduled task. You don't mention if you're actually opening Excel to update the spreadsheet, or just loading an Excel-formatted file and tweaking it. That's a big difference between the two.

A common debugging trick is wrapping your command line in CMD, so it can pipe the output to a log file.

Command: cmd.exe
Arguments:

/c :\Users\truck\AppData\Local\Programs\Python\Python314\python.exe G:\workspace\apples\temp-forecast.py > G:\workspace\apps\log.txt

geoB · Apr 25, 2026

@pepanee , @garlin : Thanks for the suggestions. Much appreciated.

I tried the ps1 option - no change. And Google's gemini gave me the cmd.exe solution. Same result. I'd just found a stackoverflow q&a that suggests that the culprit is python's xlwings. I'll poke at that tomorrow and report back.

garlin · Apr 25, 2026

From that post, it sounds like you need to allow the script to run inside a CMD window that pops up (which you can minimize) and leave it alone until it finishes.

- Run only when user is logged on (interactive session)
- Don't need Highest Privileges (will run under a different user profile than you, which probably has Python environment settings)

Command: cmd.exe
Arguments: /c start "" /min G:\Users\truck\AppData\Local\Programs\Python\Python314\python.exe G:\workspace\apples\temp-forecast.py

Try3 · Apr 26, 2026

geoB said:
Run whether or not logged in: Checked

Clear that & retry.
That entry is, in general, incompatible with any procedure that calls up a user interface.

Denis

Eksy61 · Apr 26, 2026

You didnt say whether your computer is awake at 3 AM.
If not, then you also need to check the option "Wake your computer to run this task"

geoB · Apr 26, 2026

@Try3 : Clearing "Run whether or not logged in" results in a prompt to identify an executable. Let's just say that's not compatible with scheduling the task for 3 AM. And yes, I've checked "Wake your computer to run this task" as the system is in sleep mode at the time.

Try3 · Apr 26, 2026

geoB said:
a prompt to identify an executable

Please post a screenshot.
Does the task run manually [right-click on it & select Run]? Has it ever done so?
Can you run any Python scripts from Task scheduler?
Do any Python forums provide guidance on using Task scheduler?

Denis

geoB · Apr 26, 2026

@Try3 I think the key piece here is whether a script can run from Task Scheduler. I tried running a script with different imports (because xlwings is suspect). The script's expected output was a list of data. The python script yielded data, the Task Scheduler yielded nothing. So I'm going to abandon the attempt to get Python to provide the data Excel needs. Instead, I'm off to see what PowerShell can do for managing codling moths.

Thanks for providing the critical tests.

Try3 · Apr 26, 2026

Some of my closest equivalents might be of interest to you such as, for example, writing a csv-formatted list of current Windows updates or initiating a RoboCopy backup script from my main disks to a backup disk or to other network computers.
- I use Task scheduler to run a VBScript and that script starts the script that I really wanted. I've been using such VBS 'intermediaries' for over a decade to initiate batch files & powershell ps1 files.
- A variation, that I've tested but not yet replaced my vbs with, substitutes the intermediary VBScript with an intermediary conhost command that starts the script that I really wanted. There are discussions at -

conhost suggestion - garlin #2 - ElevenForum

conhost example - jak22 post #19 - ElevenForum

- I leave all such TS tasks as Run only when user is logged on even if I set the Run with highest privileges property.
- I have experimented with Run whether user is logged on or not tasks but do not currently need any such facilities.
- In all my vbs scripts [& conhost replacements], I actually trigger shortcuts to the scripts that I really wanted so that they run minimised & with icons of my choosing.

I have also experimented with using ps1 scripts to write to Excel files but I only got as far as accessing the Excel data not writing it.
~~How to manipulate Excel files with PowerShell - TechSpi~~
Target page no longer available - old pdf printout attached instead.
I also kept this link [but annotated it as not yet tested]
export to excel - Stack Overflow

Best of luck,
Denis

geoB · Apr 26, 2026

When in ~~Rome~~ Microsoft, do as the ~~Romans~~ PowerShells do. The entire ps1 script is only 5 lines vs 29 of python. See below:

Code:

$data_url = "https://api.open-meteo.com/v1/forecast?latitude=39.49&longitude=-119.9&daily=sunset&hourly=temperature_2m&timezone=America%2FLos_Angeles&past_days=7&forecast_days=7&temperature_unit=fahrenheit&format=xlsx"
Invoke-WebRequest -Uri $data_url -OutFile "G:\workspace\apples\data.xlsx"
$date_sheet = "G:\workspace\apples\data.xlsx"
$destination = "G:\workspace\apples\sunset-temps.xlsx"
Import-Excel -Path $date_sheet | Export-Excel -Path $destination -WorksheetName "Data"

Try3 · Apr 26, 2026

geoB said:
The entire ps1 script is only 5 lines

That's interesting, thanks.
I "intend", in the fullness of time, when the time is right, to improve one of my VBScripts to write directly to an Excel spreadsheet,
- It currently writes its output to a csv file which I then open in Excel manually and save as xlsx so your example looks helpful.

All the best,
Denis

garlin · Apr 26, 2026

Here's more on the ImportExcel module: https://github.com/dfinke/ImportExcel

geoB · Apr 26, 2026

I was truly overzealous. The 5 line solution was posted without a test. Test failed. Lesson = Be excruciatingly precise when asking AI how to do something. When so applied I got a 29 line solution that actually worked. Do I need to try to shrink it? No. I'm just noodling. Here's what AI said and the chart that was made:

Code:

# 1. Configuration
$sourceUrl = "https://api.open-meteo.com/v1/forecast?latitude=39.49&longitude=-119.9&daily=sunset&hourly=temperature_2m&timezone=America%2FLos_Angeles&past_days=7&forecast_days=7&temperature_unit=fahrenheit&format=xlsx"
$fileA = "G:\workspace\apples\data.xlsx" # Temporary location for downloaded file
$fileB = "G:\workspace\apples\sunset-temps.xlsx" # Target local file
$targetSheetName = "Data"

# 2. Download Excel file "A"
Invoke-WebRequest -Uri $sourceUrl -OutFile $fileA

# 3. Open Excel and both workbooks
$excel = New-Object -ComObject Excel.Application
$excel.Visible = $false
$excel.DisplayAlerts = $false # Suppress overwrite prompts

$wbA = $excel.Workbooks.Open($fileA)
$wbB = $excel.Workbooks.Open($fileB)

# 4. Access and clear the named sheet in File "B"
$wsB = $wbB.Sheets.Item($targetSheetName)
$wsB.UsedRange.ClearContents() # Clears data but keeps formatting

# 5. Copy content from File "A" (First Sheet) to File "B"
$wsA = $wbA.Sheets.Item(1)
$wsA.UsedRange.Copy()
$wsB.Paste($wsB.Range("A1"))

# 6. Save and Clean up
$wbB.Save()
$wbA.Close($false)
$wbB.Close($true)
$excel.Quit()

# Release COM objects from memory
[System.Runtime.Interopservices.Marshal]::ReleaseComObject($excel) | Out-Null
Remove-Variable excel

thecaretaker · Apr 26, 2026

I'm only a novice here and maybe barking up the wrong tree, but, but recently I had an issue with Task Scheduler running a script. It was working fine until a Windows Update changed something a few months ago. It just wouldn't run even pressing the run option. But by switching the user from my own user account to SYSTEM it works perfectly again. It also runs silently in the background now without anything showing on the screen. Might be worth a try.

garlin · Apr 26, 2026

In this case, SYSTEM would not be the right identity. Python normally installs environment settings to your user profile. SYSTEM wouldn't have those settings.

The reason you need SYSTEM is you have "logged on or not" checked, which means only SYSTEM has the privileges to run a process (not owned by you) in your desktop session. If you chose "only when user logged on", then "Run with highest privileges" works well enough.

geoB · Apr 28, 2026

After a whole bunch of poking around, I was able to turn the solution into 7 lines! The "magic" is in dfinke's Import-Excel.

Import-Module G:\Documents\WindowsPowerShell\Modules\ImportExcel
$sourceUrl = "https://api.open-meteo.com/v1/forecast?latitude=39.49&longitude=-119.9&daily=sunset&hourly=temperature_2m&timezone=America/Los_Angeles&past_days=7&forecast_days=7&temperature_unit=fahrenheit&format=xlsx"
$data_table = "G:\workspace\apples\data.xlsx" # Temporary location for downloaded file
Export-Excel -Path $data_table -WorksheetName "Sheet1" -ClearSheet
Invoke-WebRequest -Uri $sourceUrl -OutFile $data_table
$sunset = "G:\workspace\apples\sunset-temps.xlsx"
Import-Excel $data_table | Export-Excel -Path $sunset -WorksheetName "Data"

The Task Scheduler components:
Program/script: C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
Arguments: -command & G:\workspace\apples\temp-forecast.ps1
Start in: G:\workspace\apples

garlin · Apr 28, 2026

The more proper method for calling a PS script is:

Command: powershell.exe

Arguments: -ExecutionPolicy Bypass -File G:\workspace\apples\temp-forecast.ps1

Start in: G:\workspace\apples

powershell.exe should be in your execution path, so you don't need the full pathname.
"-ExecutionPolicy Bypass" will allow this script to run this one instance, even if your current PS execution policy doesn't allow scripts.

geoB · Apr 28, 2026

@garlin Thanks for your comment. I had indeed wandered off the reservation with too many iterations. I've updated and tested my script with the more proper method. All is well.

Task Scheduler fails; command line succeeds

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