diff --git a/apps/soundcraft-web/src/web.rs b/apps/soundcraft-web/src/web.rs
index 02f1e13..452e807 100644
--- a/apps/soundcraft-web/src/web.rs
+++ b/apps/soundcraft-web/src/web.rs
@@ -67,7 +67,9 @@ enum Purpose {
 }
 
 const SESSION_EXTS: &[&str] = &[io::BUNDLE_EXTENSION, soundcraft_model::SESSION_EXTENSION];
-const AUDIO_EXTS: &[&str] = &["wav", "wave", "bwf", "aif", "aiff", "aifc", "flac", "mp3", "ogg", "oga", "m4a", "aac", "mp4", "caf", "mkv", "webm"];
+const AUDIO_EXTS: &[&str] = &[
+    "wav", "wave", "bwf", "aif", "aiff", "aifc", "flac", "mp3", "ogg", "oga", "m4a", "m4b", "aac", "mp4", "caf", "mkv", "webm",
+];
 const MIDI_EXTS: &[&str] = &["mid", "midi", "smf"];
 
 impl Purpose {
diff --git a/apps/soundcraft/src/main.rs b/apps/soundcraft/src/main.rs
index 28723b7..1931d2c 100644
--- a/apps/soundcraft/src/main.rs
+++ b/apps/soundcraft/src/main.rs
@@ -162,7 +162,7 @@ fn services() -> Services {
                 "file.import_midi" => d.add_filter("MIDI", &["mid", "midi", "smf"]),
                 _ => d.add_filter(
                     "Audio",
-                    &["wav", "wave", "bwf", "aif", "aiff", "aifc", "flac", "mp3", "ogg", "oga", "m4a", "aac", "mp4", "caf", "mkv", "webm"],
+                    &["wav", "wave", "bwf", "aif", "aiff", "aifc", "flac", "mp3", "ogg", "oga", "m4a", "m4b", "aac", "mp4", "caf", "mkv", "webm"],
                 ),
             };
             d.pick_file().map(|p| p.to_string_lossy().into_owned())
diff --git a/crates/audio-io/src/lib.rs b/crates/audio-io/src/lib.rs
index 87241c6..0e3fdd9 100644
--- a/crates/audio-io/src/lib.rs
+++ b/crates/audio-io/src/lib.rs
@@ -187,7 +187,7 @@ fn detect_by_ext(ext: &str) -> FileFormat {
         "flac" => FileFormat::Flac,
         "mp3" | "mp2" | "mp1" => FileFormat::Mp3,
         "ogg" | "oga" => FileFormat::Ogg,
-        "aac" | "m4a" | "mp4" | "adts" => FileFormat::Aac,
+        "aac" | "m4a" | "m4b" | "mp4" | "adts" => FileFormat::Aac,
         "caf" => FileFormat::Caf,
         _ => FileFormat::Other,
     }
diff --git a/crates/audio-io/tests/malformed.rs b/crates/audio-io/tests/malformed.rs
index 1cec656..384e4bf 100644
--- a/crates/audio-io/tests/malformed.rs
+++ b/crates/audio-io/tests/malformed.rs
@@ -240,6 +240,7 @@ fn detect_format_by_magic_and_hint() {
     assert_eq!(detect_format(b"", Some(".WAV")), FileFormat::Wav);
     assert_eq!(detect_format(b"zz", Some("aif")), FileFormat::Aiff);
     assert_eq!(detect_format(b"zz", Some("m4a")), FileFormat::Aac);
+    assert_eq!(detect_format(b"zz", Some("M4B")), FileFormat::Aac);
     assert_eq!(detect_format(b"zz", Some("flac")), FileFormat::Flac);
     assert_eq!(detect_format(b"zz", Some("xyz")), FileFormat::Other);
     assert_eq!(detect_format(b"zz", None), FileFormat::Other);
diff --git a/crates/ui-egui/src/windows.rs b/crates/ui-egui/src/windows.rs
index 12b3540..2b280cf 100644
--- a/crates/ui-egui/src/windows.rs
+++ b/crates/ui-egui/src/windows.rs
@@ -334,7 +334,7 @@ fn workspace(app: &mut SoundApp, ctx: &egui::Context) {
                         }
                         let is_dir = e.file_type().is_ok_and(|t| t.is_dir());
                         let ext = std::path::Path::new(&name).extension().and_then(|x| x.to_str()).unwrap_or("").to_ascii_lowercase();
-                        (is_dir || ["wav", "aif", "aiff", "flac", "mp3", "ogg", "m4a", "caf", "mid", "midi", "scraft"].contains(&ext.as_str()))
+                        (is_dir || ["wav", "aif", "aiff", "flac", "mp3", "ogg", "m4a", "m4b", "caf", "mid", "midi", "scraft"].contains(&ext.as_str()))
                             .then_some((name, is_dir))
                     })
                     .collect()