*** title: Troubleshoot performance tests in Postman updated: 2026-02-18T00:00:00.000Z max-toc-depth: 2 ---------------- If you encounter issues while running performance tests in Postman, here are some troubleshooting steps you can follow. ## Initialization error The first time you start a performance test, Postman performs a one-time setup by downloading and installing a performance runner extension in the background. This extension is required to handle local data processing and high-load testing. You may experience an initialization error if your local environment or network restrictions prevent the extension from downloading or installing. Once the runner extension is successfully installed, later performance tests won't require more downloads. ### Common error messages In your Postman app logs, you may encounter the following error messages: * `Timeout downloading https://performance-test-artifacts.getpostman.com/...` * `self signed certificate in certificate chain` or `unable to get local issuer certificate` * `An Application Control policy has blocked this file` * `Client network socket disconnected before secure TLS connection was established` Postman app logs are located in the following directory: * **Windows**: `%AppData%\Postman\logs` * **macOS**: `~/Library/Application Support/Postman/logs` * **Linux**: `~/.config/Postman/logs` ### Possible solutions Try the following solutions to resolve the issue: * **Allowlist Postman domains** - If your organization operates behind a firewall, background downloads may be blocked. Your IT team may need to allowlist the `performance-test-artifacts.getpostman.com` domain. * **Resolve proxy certificates** - If your organization uses a proxy server that performs SSL inspection, Postman may block the installation if your system doesn't recognize the certificate. You may need to add your organization's proxy certificate to your system's trusted root certificates, like macOS Keychain. * **Update application control policies** - Your organization's security tools may block unrecognized binaries in the user home directory. Your IT team may need to allow Postman-managed binaries in the following directory: * **Windows**: `%AppData%\Roaming\Postman\*` * **macOS**: `~/Library/Application Support/Postman/*` * **Linux**: `~/.config/Postman/*` * **Check installation logs** - Check your Postman app logs to identify the specific issue. In the `main.logs` file, look for entries tagged with `PerformanceTestV2` or messages mentioning `Error`. Check with your IT team if the issue is a result of a certificate or network issue. If this didn't resolve your issue, contact [Postman support](https://www.postman.com/support/) to share your log files.