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FixMyError.net
Windows New Added 26 October 2026

PowerShell: WARNING: Unable to resolve package source

Windows PowerShell 5.1 runs on .NET Framework, which on older or unpatched systems still offers only TLS 1.0 and 1.1 by default, and the PowerShell Gallery has required TLS 1.2 since 2020. The handshake fails, so Install-Module reports the gallery as unreachable even though a browser on the same machine opens it fine. An authenticating proxy produces the same warning. PowerShell 7 is not affected, because it runs on modern .NET.

Quick fix

Read the commands before running them. Anything that restarts a service, deletes data or changes permissions should be tried on a non-production system first.

Quick fix
# Which protocols is this session offering?
[Net.ServicePointManager]::SecurityProtocol

# "Could not create SSL/TLS secure channel" here confirms it is TLS
Invoke-WebRequest https://www.powershellgallery.com/api/v2 -UseBasicParsing | Select-Object StatusCode

# Fix for this session: add TLS 1.2, then update the tooling
[Net.ServicePointManager]::SecurityProtocol = [Net.ServicePointManager]::SecurityProtocol -bor [Net.SecurityProtocolType]::Tls12
Install-PackageProvider -Name NuGet -MinimumVersion 2.8.5.201 -Force
Install-Module PowerShellGet -Force -AllowClobber

# Permanent fix for every .NET Framework app (run as administrator)
Set-ItemProperty -Path 'HKLM:\SOFTWARE\Microsoft\.NETFramework\v4.0.30319' -Name SchUseStrongCrypto -Value 1 -Type DWord
Set-ItemProperty -Path 'HKLM:\SOFTWARE\Wow6432Node\Microsoft\.NETFramework\v4.0.30319' -Name SchUseStrongCrypto -Value 1 -Type DWord

# Behind a proxy that wants your Windows credentials
[System.Net.WebRequest]::DefaultWebProxy.Credentials = [System.Net.CredentialCache]::DefaultNetworkCredentials

How to diagnose Windows errors

Windows errors surface as numeric codes that mean little on their own, but the operating system keeps detailed logs that almost always contain the real cause. Two categories dominate developer machines: missing Visual C++ redistributables (a DLL-not-found error for a runtime the application assumed was present) and architecture or dependency mismatches (the 0xc000007b family, usually a 32-bit/64-bit mix).

If the quick fix above does not resolve it, work through these steps. They apply to this whole class of error, not just to this one message, which is usually what saves the time.

  1. Read Event Viewer under Windows Logs → Application and System, filtered to the time of the failure. The numeric code in the dialog maps to a detailed entry there.
  2. For MSI failures, install with verbose logging: msiexec /i package.msi /l*v install.log, then search the log for "Return value 3". The lines just above name the failing action.
  3. For missing DLLs, install the matching Visual C++ Redistributable and confirm the architecture matches the application (x64 versus x86).
  4. Repair system corruption with sfc /scannow followed by DISM /Online /Cleanup-Image /RestoreHealth, in that order.
  5. For access-denied errors, check both NTFS permissions and whether the process needs elevation; UAC virtualisation can make writes appear to succeed while landing elsewhere.

Tools worth reaching for

  • Event Viewer
  • msiexec /l*v
  • sfc /scannow
  • DISM /RestoreHealth
  • Process Monitor (ProcMon)

Authoritative references

Primary documentation for this error, worth reading before applying any fix in production.

devblogs.microsoft.com learn.microsoft.com

Related Windows errors

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Something missing or wrong?

This entry is maintained by hand. If the fix is out of date, incomplete, or you have a better one, email a correction and it will be reviewed.