diff --git a/README.md b/README.md
index 7a228ad..5f42a42 100644
--- a/README.md
+++ b/README.md
@@ -89,8 +89,10 @@ and start the app again.
 
 Grab `usage-monitor.exe` from the
 [Releases page](https://github.com/tiennm99/usage-monitor/releases/latest).
-Put it anywhere on disk (e.g. `%LOCALAPPDATA%\UsageMonitor\`) and
-run it. The app self-updates from the same Releases feed.
+Put it in a folder of its own that you can write to (e.g.
+`%LOCALAPPDATA%\UsageMonitor\`) and run it. The app is portable: it keeps
+`settings.json` next to the exe, so moving the folder keeps your settings. It
+self-updates from the same Releases feed.
 
 **First-run note:** the binary is unsigned, so SmartScreen will show
 "Windows protected your PC". Click **More info** → **Run anyway**. Code
@@ -103,7 +105,9 @@ From the same
 pick one:
 
 - `usage-monitor_X.Y.Z_amd64.AppImage`: make it executable
-  (`chmod +x`) and run it. The AppImage self-updates in place.
+  (`chmod +x`) and run it. Like the Windows exe it is portable and keeps
+  `settings.json` next to the AppImage file, so give it a folder you can
+  write to. The AppImage self-updates in place.
 - `usage-monitor_X.Y.Z_amd64.deb`: install it with
   `sudo apt install ./usage-monitor_X.Y.Z_amd64.deb`. The app
   still checks for updates, but installing one is left to you: download the
@@ -209,8 +213,9 @@ Settings are saved to:
 
 | OS | Settings file |
 |----|---------------|
-| Windows | `%APPDATA%\UsageMonitor\settings.json` |
-| Linux | `$XDG_CONFIG_HOME/UsageMonitor/settings.json`, usually `~/.config/UsageMonitor/settings.json` |
+| Windows | `settings.json` next to `usage-monitor.exe` |
+| Linux AppImage | `settings.json` next to the `.AppImage` file |
+| Linux `.deb` | `$XDG_CONFIG_HOME/UsageMonitor/settings.json`, usually `~/.config/UsageMonitor/settings.json` |
 
 Other files the app writes:
 
diff --git a/docs/release-process.md b/docs/release-process.md
index 0226417..00465d6 100644
--- a/docs/release-process.md
+++ b/docs/release-process.md
@@ -119,8 +119,9 @@ updater code at v0.4.0, v0.4.1 and v0.5.0, they need:
   `updates/updater-helper-*.exe` files they leave behind.
 
 Since the rename, an upgraded install starts with default settings and
-keeps any autostart entry the legacy app registered: the settings folder
-and autostart entry names changed, and nothing migrates them. See
+keeps any autostart entry the legacy app registered: settings now live in
+`settings.json` next to the exe, the autostart entry name changed, and
+nothing migrates either. See
 [the rename plan](../plans/261021-1226-rename-to-usage-monitor/plan.md).
 
 `scripts/make-latest-json.js` enforces the asset rules before
diff --git a/plans/261021-1226-rename-to-usage-monitor/plan.md b/plans/261021-1226-rename-to-usage-monitor/plan.md
index 3cdff3a..ba690ab 100644
--- a/plans/261021-1226-rename-to-usage-monitor/plan.md
+++ b/plans/261021-1226-rename-to-usage-monitor/plan.md
@@ -41,8 +41,9 @@ merges into `main`.
 
 ## Accepted costs
 
-- Installs that upgrade start with default settings, because the settings
-  folder name changed and nothing migrates it.
+- Installs that upgrade start with default settings: the portable Windows
+  exe and the AppImage now keep `settings.json` next to the file, and nothing
+  migrates the old one.
 - On Windows, an install that had autostart on keeps its old Run entry, which
   points at the same exe file. Turning autostart on in the new app adds a
   second entry.
diff --git a/src/core/settings.rs b/src/core/settings.rs
index 309cf22..b037393 100644
--- a/src/core/settings.rs
+++ b/src/core/settings.rs
@@ -1,6 +1,7 @@
-// Persisted settings. The path, schema, key names and physical-px positions
-// stay byte-compatible with the Win32 builds, so no migration step exists.
+// Persisted settings. The schema, key names and physical-px positions stay
+// byte-compatible with the Win32 builds.
 
+use std::ffi::OsString;
 use std::path::{Path, PathBuf};
 
 use serde::{Deserialize, Serialize};
@@ -8,6 +9,7 @@ use serde::{Deserialize, Serialize};
 use crate::core::geom::{
     position_on_any_monitor, Rect, DEFAULT_BUBBLE_SIZE, MAX_BUBBLE_SIZE, MIN_BUBBLE_SIZE,
 };
+use crate::update::channel::Channel;
 use crate::usage::ProviderId;
 
 pub const APP_DIR_NAME: &str = "UsageMonitor";
@@ -187,8 +189,33 @@ impl Settings {
     }
 }
 
+/// The folder holding `settings.json`. The Windows exe and the AppImage are
+/// portable, so their settings sit next to the file and move with it. A
+/// `.deb` install lives in a read-only system folder and keeps them in the
+/// user's config folder.
 pub fn settings_dir() -> Option<PathBuf> {
-    dirs::config_dir().map(|d| d.join(APP_DIR_NAME))
+    portable_dir(
+        crate::update::channel::current(),
+        std::env::var_os("APPIMAGE"),
+        std::env::current_exe().ok(),
+    )
+    .or_else(|| dirs::config_dir().map(|d| d.join(APP_DIR_NAME)))
+}
+
+/// The folder of the portable file for `channel`: the exe on Windows, the
+/// AppImage file (not its temporary mount) on Linux. `None` for installs
+/// that are not portable.
+fn portable_dir(
+    channel: Channel,
+    appimage: Option<OsString>,
+    exe: Option<PathBuf>,
+) -> Option<PathBuf> {
+    let file = match channel {
+        Channel::Portable => exe?,
+        Channel::AppImage => PathBuf::from(appimage?),
+        Channel::PackageManager | Channel::Unsupported => return None,
+    };
+    file.parent().map(Path::to_path_buf)
 }
 
 pub fn settings_path() -> PathBuf {
@@ -275,6 +302,37 @@ pub fn save_to(path: &Path, settings: &Settings) -> std::io::Result<()> {
 mod tests {
     use super::*;
 
+    #[test]
+    fn portable_installs_keep_settings_next_to_the_file() {
+        let folder = Path::new("Tools").join("Usage");
+        assert_eq!(
+            portable_dir(
+                Channel::Portable,
+                None,
+                Some(folder.join("usage-monitor.exe"))
+            ),
+            Some(folder)
+        );
+        // The AppImage file's folder, not the mount the exe runs from.
+        assert_eq!(
+            portable_dir(
+                Channel::AppImage,
+                Some(OsString::from("/home/u/Apps/usage-monitor.AppImage")),
+                Some(PathBuf::from("/tmp/.mount_usage/usr/bin/usage-monitor")),
+            ),
+            Some(PathBuf::from("/home/u/Apps"))
+        );
+        assert_eq!(
+            portable_dir(
+                Channel::PackageManager,
+                None,
+                Some(PathBuf::from("/usr/bin/usage-monitor"))
+            ),
+            None
+        );
+        assert_eq!(portable_dir(Channel::Unsupported, None, None), None);
+    }
+
     #[test]
     fn old_two_provider_settings_json_still_loads() {
         let json = r#"{