Installation Script Fails on Windows PowerShell 5.1

[justavik]

Bug Report: Installation Script Fails on Windows PowerShell 5.1

Environment

• OS: Windows 10/11
• PowerShell Version: 5.1 (Windows PowerShell - default Windows installation)
• Running as Administrator: Yes

Expected Behavior

The installation script should work with both Windows PowerShell 5.1 (default) and PowerShell Core.

Actual Behavior

Script fails immediately with "[ERROR] This installer is for Windows only." when run in Windows PowerShell 5.1, despite being on Windows.

Root Cause

The script uses $IsWindows variable for OS detection, which only exists in PowerShell Core (6.0+). In Windows PowerShell 5.1, this variable is $null, causing the condition if (-not $IsWindows) to evaluate as true.

Steps to Reproduce

1. Open Windows PowerShell 5.1 as Administrator (default PowerShell on Windows)
2. Run: iex ((New-Object System.Net.WebClient).DownloadString('https://vapi.ai/install.ps1'))
3. Script fails with Windows detection error

Workaround

Use PowerShell Core instead:

pwsh -Command "iex ((New-Object System.Net.WebClient).DownloadString('https://vapi.ai/install.ps1'))"

[goosewin]

This should have been addressed in #4 that I just merged.

The new install script should now be live - please let me know if you're still facing any issues!

[justavik]

All good now Dan. Cheers!

…

On Fri, 11 Jul 2025, 03:20 Dan Goosewin, ***@***.***> wrote: *goosewin* left a comment (VapiAI/cli#2) <#2 (comment)> This should have been addressed in #4 <#4> that I just merged. The new install script should now be live - please let me know if you're still facing any issues! — Reply to this email directly, view it on GitHub <#2 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AU4W2WQ4KGPLJG2VT6MNJUD3H3N2XAVCNFSM6AAAAACBCAU3SSVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTANJZGIYTGMRUGY> . You are receiving this because you authored the thread.Message ID: ***@***.***>

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