Quick Answer
haskell-exe is safe. It's the Glasgow Haskell Compiler's runtime launcher that powers compiled Haskell binaries and manages memory, threads, and I/O within the program.
Is it a Virus?
✔ NO - Safe
Typically located in C:\Program Files\Haskell\haskell-exe.exe or C:\Haskell\bin\haskell-exe.exe; verify the digital signature.
Why is there a separate haskell-exe process?
The GHC runtime usually runs as a single process with multiple threads; seeing multiple haskell-exe processes can indicate a separate helper program or malware masquerading as haskell-exe.
Check for signed, legitimate processes in Task Manager.
Can I Disable?
✔ YES
Terminate the process or prevent startup; do not disable critical runtime if you run Haskell apps.
What is haskell-exe?
haskell-exe is the runtime executable used by programs compiled with the Glasgow Haskell Compiler (GHC). It launches the Haskell runtime system, loads the compiled program, and runs main, coordinating memory, concurrency, and I/O within the application. Each standalone Haskell binary includes its own RTS invoked by this executable.
Technically, haskell-exe initializes the GHC runtime, sets up the garbage collector, manages lightweight threads (green threads), handles I/O, and executes the program's main function. It is embedded in the compiled binary and not a separate interpreter.
Quick Fact: GHC's RTS design enables lazy evaluation and lightweight threading inside a single native executable, reducing inter-process communication needs.
Types of Runtime Components
- Main Runtime Process: The primary haskell-exe instance that starts the program and hosts the RTS.
- RTS Scheduler: Schedules lightweight threads (green threads) within the process.
- Garbage Collector: Manages memory for the Haskell heap and performs collection.
- I/O System: Handles file, network, and console I/O for the program.
- Foreign Function Interface: Allows calling into C libraries from Haskell code.
- Asynchronous Tasks: Background tasks and non-blocking operations run under RTS.
Is haskell-exe Safe?
Yes, haskell-exe is safe when it originates from legitimate GHC builds or official Haskell distributions and is located in expected directories.
Is haskell-exe a Virus or Malware?
The real haskell-exe is not a virus. Malware may mimic names to evade detection.
How to Tell if haskell-exe is Legitimate or Malware
- File Location: Must be in
C:\Program Files\Haskell\haskell-exe.exe or C:\Haskell\bin\haskell-exe.exe. Any other path is suspicious.
- Digital Signature: Right-click the file in Explorer -> Properties -> Digital Signatures. Should show signer like "GHC Project" or "The Haskell Platform Maintainers".
- Resource Usage: Normal usage is 1-15% CPU per process; 50-150 MB memory. Excessive idle usage is suspicious.
- Behavior: The runtime should run only when the associated Haskell program is active. Background processes without a program may indicate malware.
Red Flags: If haskell-exe is located in unusual folders (e.g., Temp, AppData\Local, or System32), runs without a visible program, lacks a valid signature, or uses resources constantly, scan with antivirus software. Watch for similarly-named files like "haskell-exe.exe" from untrusted sources.
Why Is haskell-exe Running on My PC?
haskell-exe runs when you execute a Haskell-compiled program or when the program is configured to run in the background for I/O tasks or services.
Reasons it's running:
- Active Haskell Application: You're actively running a Haskell program; haskell-exe launches the RTS to execute main.
- Background Threads: GHC uses lightweight threads that may continue running while the app performs I/O or awaits events.
- Startup Configuration: The program may be set to start automatically at Windows startup or user login.
- Background I/O or Networking: Asynchronous I/O, network listeners, or event loops may keep the RTS active.
- FFI or External Libraries: Native libraries called via the Foreign Function Interface can spawn work in the RTS, extending runtime activity.
Can I Disable or Remove haskell-exe?
Yes, you can disable haskell-exe. If you don't run Haskell programs, you can uninstall or disable the runtime; otherwise, disabling may affect running applications.
How to Stop haskell-exe
- End Program: Close the Haskell application window or use its in-app exit.
- End RTS Threads: Open Task Manager (Ctrl+Shift+Esc), locate haskell-exe, and End Task.
- Prevent Startup: Task Manager > Startup tab > Disable the Haskell program entry, if present.
- Stop Background Apps: If the app offers a background mode, disable it in the app settings rather than system-wide.
How to Uninstall Haskell Runtime
- ✔ Windows Settings → Apps → Apps & Features → select the Haskell distribution or program → Uninstall
- ✔ Control Panel → Programs → Uninstall a program → select Haskell distribution → Uninstall
- ✔ Remove remaining folders: C:\Program Files\Haskell and any related user data directories
Common Problems: High CPU or Memory Usage
If haskell-exe is consuming excessive resources:
Common Causes & Solutions
- Large number of concurrent threads: Limit concurrency or adjust RTS options; consider using -N to cap capabilities.
- Inefficient algorithms or data structures: Profile with ghc-prof, optimize hot paths, add strictness where appropriate.
- Memory leaks in Haskell code: Use heap profiling and GC tuning (-M, -H) to identify leaks and optimize memory usage.
- Heavy or stale libraries: Update to the latest libraries and GHC version; recompile to ensure compatibility.
- FFI calls to slow native code: Benchmark and optimize native calls; minimize crossing the FFI boundary.
- Background I/O or watchers: Review and disable unnecessary background services or watchers in the application.
Quick Fixes:
1. Open the Haskell program and use in-app task controls to terminate heavy tasks
2. Check for unnecessary background processes and disable them in the app settings
3. Update to the latest Haskell distribution and recompile
4. Run with RTS profiling: ghc --profile and analyze hotspots
5. Adjust garbage collector settings via RTS options (-C, -M, -H)
Frequently Asked Questions
Is haskell-exe safe?
Yes, the legitimate haskell-exe from a GHC distribution is safe. Verify it is located in C:\Program Files\Haskell\haskell-exe.exe or a related bin directory and that it carries a valid digital signature from the GHC project.
Why is haskell-exe using so much CPU?
High CPU often comes from active computations in a Haskell program, heavy I/O, or inefficient code. Use Task Manager to identify the process, then profile the code or optimize hot paths and libraries.
Can I delete haskell-exe?
If you do not run Haskell programs, you can uninstall the runtime distribution. Deleting the runtime without removing the associated program may break that program.
Can I disable haskell-exe?
Yes. Stop the running program, end the haskell-exe task, and disable startup entries if present. Ensure you do not disable essential runtime for your Haskell apps.
Why is haskell-exe running at startup?
Some Haskell programs configure to launch at login for background processing. Disable startup in Task Manager > Startup or within the app's own settings.
How do I verify haskell-exe authenticity?
Check file path (C:\Program Files\Haskell\...), digital signature in Properties, and compare version/signature with the official GHC release notes.