Allow PowerShell Scripts on Windows 7 - Execution Policy

PowerShell Script Execution Errors and Resolution

Attempting to execute a downloaded script without prior PowerShell configuration often results in a prominent error message displayed in red text. This can be disconcerting for many users, but a straightforward solution exists.

PowerShell employs various execution modes to regulate the types of code it's permitted to run. These modes are determined by a registry key located within the HKLM hive. Four distinct execution policies are available:

• Restricted: This is the default policy, allowing only interactive commands and preventing script execution.
• All Signed: Scripts and configuration files require a digital signature from a trusted publisher to run. This introduces a potential risk of executing malicious scripts if the publisher is compromised.
• Remote Signed: Locally created scripts can run without a signature. However, any script downloaded from the internet, including those accessed via UNC paths, must be digitally signed.
• Unrestricted: All scripts and configuration files are executed without signature requirements. Confirmation is requested when running files originating from internet-based applications like Outlook or Internet Explorer, but the risk of executing unsigned, malicious scripts is present.

The default PowerShell execution policy is Restricted. In this mode, PowerShell functions primarily as an interactive shell. Scripts are not executed, and only configuration files signed by a trusted publisher are loaded. The red error you encounter is most likely due to attempting to run an unsigned script.

A secure approach is to temporarily modify the Execution Policy to Unrestricted, execute your script, and then immediately revert it back to Restricted.

To switch to the Unrestricted policy, execute the following command within an administrative PowerShell session:

Set-ExecutionPolicy Unrestricted

A confirmation prompt will appear; press Enter to proceed with the change.