# macOS: dyld: Symbol not found: _SecTrustCopyCertificateChain — Expected in: /System/Library/Frameworks/Security.framework

**Code:** `dyld: Symbol not found` · **Category:** macOS · **Seen on:** macOS

A program was built for a newer macOS (or different library version) than the one running, so a function it needs isn't there.

## Meaning

The app targets a newer SDK/OS. Update macOS, install a build for your OS version, or rebuild with a lower deployment target (`MACOSX_DEPLOYMENT_TARGET`). For Homebrew bottles, `brew upgrade` or rebuild from source with `--build-from-source`.

## Common causes

- Binary built on newer macOS than the running one
- Library version mismatch after partial upgrade
- Wrong deployment target
- Homebrew bottle for newer OS
- Stale prebuilt wheels/modules

## Quick fix

1. Update macOS or install a compatible version
2. Rebuild with `MACOSX_DEPLOYMENT_TARGET=12.0`
3. `brew reinstall --build-from-source PACKAGE`

## Detailed fix by platform

### macOS

1. `sw_vers` and `otool -l binary | grep -A3 LC_BUILD_VERSION`

## How to diagnose

1. **OS** — Running vs required?
2. **Target** — Deployment version?
3. **Source** — Rebuild possible?

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Source: [WhatIsMyError](https://whatismyerror.com/errors/macos/dyld-symbol-not-found)