How to Fix the Positional Parameter Error in PowerShell

Learn how to resolve the PowerShell positional parameter error when adding exclusions to Microsoft Defender. Follow this detailed guide to fix your script!
---

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: How do I fix this positional parameter error (PowerShell)?

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Understanding the Problem: Positional Parameter Error in PowerShell

If you've ever encountered errors while running PowerShell scripts, you're not alone. One common issue that users face is the "A positional parameter cannot be found that accepts argument" error. This specific error occurs when the script you're trying to execute has incorrect syntax, particularly with how parameters are passed.

In this guide, we'll delve into a specific example of this error and how to resolve it effectively. Our focus will be on a user who encountered this problem when trying to set an exclusion path for Microsoft Defender using PowerShell commands.

The Scenario

In the given scenario, the user attempts to execute the following PowerShell instruction:

[[See Video to Reveal this Text or Code Snippet]]

However, upon execution, they receive the following error message:

[[See Video to Reveal this Text or Code Snippet]]

To compound the confusion, the following command works perfectly fine:

[[See Video to Reveal this Text or Code Snippet]]

Identifying the Issue

The key misunderstanding here lies in how PowerShell treats the commands being passed to Start-Process. The error arises because PowerShell is misinterpreting the syntax you used in the first command. Specifically, using braces {} for the command block is causing issues with parameter recognition.

When commands are enclosed within {}, PowerShell expects a specific set of parameters, and the way Start-Process is called does not align with those expectations. This leads to the positional parameter error you faced.

The Solution: Correcting the Syntax

To fix the issue, you'll need to change how you're invoking the command with Start-Process. Instead of using braces, you should provide the command as a double-quoted string. Here's how to properly structure your command:

[[See Video to Reveal this Text or Code Snippet]]

Breakdown of the Command

Start-Process: This cmdlet is used to start one or more processes on your computer.

powershell: Specifies that a new PowerShell instance will be started.

"Add-MpPreference -ExclusionPath 'my/path/to/exe'": The corrected command where we are using a double-quoted string to ensure all parts are correctly parsed.

-Verb "RunAs": This parameter allows the command to request elevated permissions (run as administrator).

Conclusion

Debugging errors in PowerShell can sometimes be daunting, especially when it comes to incorrect syntax. By understanding how to properly format your commands and utilize double-quoted strings, you can avoid common pitfalls such as the positional parameter error.

With the corrected command in hand, you should now be able to successfully add paths to your Microsoft Defender exclusions without facing further issues. Happy scripting!