diff --git a/apps/effectcraft-cli/tests/cli.rs b/apps/effectcraft-cli/tests/cli.rs
index 62aefd5d..bd5d5002 100644
--- a/apps/effectcraft-cli/tests/cli.rs
+++ b/apps/effectcraft-cli/tests/cli.rs
@@ -25,12 +25,19 @@ fn ok_json(args: &[&str]) -> Value {
     v
 }
 
+/// `std::fs::canonicalize` without Windows' `\\?\` verbatim prefix, which a child's `current_dir()` never reports.
+fn canonical(path: &std::path::Path) -> std::io::Result<PathBuf> {
+    let path = std::fs::canonicalize(path)?;
+    let plain = path.to_str().and_then(|s| s.strip_prefix(r"\\?\")).filter(|s| s.as_bytes().get(1) == Some(&b':'));
+    Ok(plain.map(PathBuf::from).unwrap_or(path))
+}
+
 fn tmp(name: &str) -> PathBuf {
     let d = std::env::temp_dir().join(format!("ec-cli-test-{}", std::process::id()));
     std::fs::create_dir_all(&d).unwrap();
     // macOS's `/var` is a symlink to `/private/var`: a child process resolves its working
     // directory through `current_dir()`, which is canonical, so compare canonical paths.
-    std::fs::canonicalize(&d).unwrap_or(d).join(name)
+    canonical(&d).unwrap_or(d).join(name)
 }
 
 #[test]
@@ -260,7 +267,7 @@ fn render_out_is_relative_to_the_working_directory() {
     std::fs::create_dir_all(&proj).unwrap();
     std::fs::create_dir_all(&elsewhere).unwrap();
     // current_dir resolves aliases such as macOS /var -> /private/var.
-    let root = root.canonicalize().unwrap();
+    let root = canonical(&root).unwrap();
     let (proj, elsewhere) = (root.join("proj"), root.join("elsewhere"));
     let project = proj.join("x.ecproj");
     let p = project.to_str().unwrap();
diff --git a/crates/host/src/lib.rs b/crates/host/src/lib.rs
index 1e5311b0..bdb4e2bc 100644
--- a/crates/host/src/lib.rs
+++ b/crates/host/src/lib.rs
@@ -290,7 +290,8 @@ mod tests {
         let mut s = super::session();
         s.exporter = Some(Arc::new(super::FileExporter { sink: Some(Arc::new(move |p: &str, d: Vec<u8>| g.lock().unwrap().push((p.to_string(), d)))) }));
         s.execute("file.openDemoProject", json!({})).unwrap();
-        let dir = "/no-such-dir-effectcraft-sink-test";
+        // Rooted without a drive letter is not absolute on Windows, where the engine joins it to the home drive.
+        let dir = if cfg!(windows) { "C:/no-such-dir-effectcraft-sink-test" } else { "/no-such-dir-effectcraft-sink-test" };
         s.execute(
             "renderQueue.add",
             json!({"format": "gif", "output": format!("{dir}/a.gif"), "resolution": 0.0625, "timeSpan": "custom", "start": 0.0, "end": 0.2}),