diff --git a/crates/femm-app/src/main.rs b/crates/femm-app/src/main.rs
index c96cefb..b1b0c33 100644
--- a/crates/femm-app/src/main.rs
+++ b/crates/femm-app/src/main.rs
@@ -2068,7 +2068,7 @@ fn compute_frame(base: FemmDoc, tracks: Vec<kinematic::Track>, frame_idx: i64, d
             title: String::from("frame save .pbc failed"),
             body:  format!("{pbc_path:?}\n\n{e}"),
         })?;
-        let tri_out = std::process::Command::new(&triangle)
+        let tri_out = quiet_command(&triangle)
             .args([
                 "-p", "-P", "-e", "-A", "-a", "-z", "-Q", "-I",
                 &format!("-q{min_angle}"),
@@ -2107,7 +2107,7 @@ fn compute_frame(base: FemmDoc, tracks: Vec<kinematic::Track>, frame_idx: i64, d
         title: String::from("femm-mag-solve binary missing"),
         body:  String::from("run `cargo xtask install`"),
     })?;
-    let solver_out = std::process::Command::new(&helper)
+    let solver_out = quiet_command(&helper)
         .arg(&stem_str)
         .output()
         .map_err(|e| ErrorReport {
@@ -2449,7 +2449,7 @@ fn run_mesh(doc: &FemmDoc) -> Result<Mesh, ErrorReport> {
         body:  format!("{stem:?}"),
     })?;
     let min_angle = if doc.min_angle > 0.0 { doc.min_angle } else { MIN_ANGLE_DEG };
-    let output = std::process::Command::new(&triangle)
+    let output = quiet_command(&triangle)
         .args([
             "-p", "-P", "-e", "-A", "-a", "-z", "-Q", "-I",
             &format!("-q{min_angle}"),
@@ -2489,7 +2489,7 @@ fn run_solve(stem: &Path) -> Result<(), ErrorReport> {
         body:  String::from("run `cargo xtask install` (or set $FEMM_MAG_SOLVE to the femm-mag-solve executable)"),
     })?;
 
-    let output = std::process::Command::new(&helper)
+    let output = quiet_command(&helper)
         .arg(stem_str)
         .output()
         .map_err(|e| ErrorReport {
@@ -2547,6 +2547,17 @@ fn unix_signal(status: &std::process::ExitStatus) -> Option<i32> {
 #[cfg(not(unix))]
 fn unix_signal(_status: &std::process::ExitStatus) -> Option<i32> { None }
 
+fn quiet_command(program: &std::path::Path) -> std::process::Command {
+    let mut cmd = std::process::Command::new(program);
+    #[cfg(windows)]
+    {
+        use std::os::windows::process::CommandExt;
+        const CREATE_NO_WINDOW: u32 = 0x0800_0000;
+        cmd.creation_flags(CREATE_NO_WINDOW);
+    }
+    cmd
+}
+
 /// resolves the femm-mag-solve helper path from the bundled app, the dev target dir, or $FEMM_MAG_SOLVE.
 fn locate_mag_solver() -> Option<std::path::PathBuf> {
     let exe_name = format!("femm-mag-solve{}", std::env::consts::EXE_SUFFIX);