Server startup failed
Symptom
The Pipeline Explorer view shows an error, or stays on Starting server… and never loads. Pipeline Explorer runs a small bundled background server for handler discovery and profiling; when it can’t start, the tree and profiler stay unavailable.
Work through the causes below in order.
1. Antivirus or endpoint protection quarantined the server
Security products sometimes quarantine freshly-installed binaries before they are widely trusted. If the bundled server file is removed or blocked from running, the extension can’t launch it.
Check
Open the extension’s installation folder and confirm the server files are present:
- VS Code — the extension’s folder under your user
.vscode/extensionsdirectory. - Visual Studio — the extension’s folder under your Visual Studio installation’s extensions directory.
If the server files are missing right after a successful install, quarantine is the likely cause.
Fix
- Restore the file from your security product’s quarantine.
- Add the extension’s installation folder to its allow-list so future updates aren’t quarantined.
- Reload the IDE.
2. The server can’t run on your platform
The bundled server is a native binary matched to your operating system and CPU architecture. If it won’t start and you’re on an uncommon platform, capture the output (see Capturing logs below) so we can help.
3. A leftover server process or stale lock
Pipeline Explorer keeps a single background server per machine and tracks it with a lock. If a previous session left a server running, or the lock points at a process that is no longer alive, the new session can fail to connect.
Fix
- VS Code — run Mediator: Stop Server from the Command Palette to stop any lingering server, then reload the window. It respawns automatically on the next refresh.
- Visual Studio — close and reopen the tool window.
- If it still won’t start, restart the machine to clear any stale state, then reopen your solution.
4. Very old Linux system libraries
On Linux, the server needs reasonably current system libraries. Very old distributions may not have them, and the server exits immediately on launch.
Fix
- Use a current LTS release of your distribution.
- Or run the extension inside a devcontainer / WSL2 image based on a current Linux.
On Windows and macOS this is rarely an issue.
Capturing logs
If you want to look closer or report the problem, capture the full output:
- VS Code — open the Output panel (
Ctrl+Shift+U) and select Mediator from the dropdown. - Visual Studio — View → Output, then select Mediator in the dropdown.
Reload the IDE so the log captures startup from the beginning, reproduce the failure, then copy the Mediator output. You can open an issue with that output plus your IDE and extension version — no project source is needed.