diff --git a/src-tauri/src/lib.rs b/src-tauri/src/lib.rs
index a7441e7..8eb1af7 100644
--- a/src-tauri/src/lib.rs
+++ b/src-tauri/src/lib.rs
@@ -625,14 +625,17 @@ fn read_file_base64(path: String) -> Result<String, String> {
 }
 
 // Resolve the main baldav.db path (same fallbacks as rebuild_roads/get_road_points) and the
-// app root (where Kotlin's FileObserver watches). Root = data_dir/../.. on Android.
+// app root = the DIRECTORY that holds baldav.db. Deriving root from data_dir/../.. is wrong:
+// app_data_dir() on Android is sometimes already the app root, so ../.. lands in /data/user
+// (not writable) — measured, VACUUM INTO failed there. The dir next to baldav.db is always
+// writable and is exactly what Kotlin (filesDir.parentFile) watches/reads.
 fn db_and_root(app: &tauri::AppHandle) -> Result<(std::path::PathBuf, std::path::PathBuf), String> {
     let data_dir = app.path().app_data_dir().map_err(|e| e.to_string())?;
     let p1 = data_dir.join("../../baldav.db");
     let p2 = data_dir.join("baldav.db");
     let p3 = std::path::PathBuf::from(data_dir.to_str().unwrap_or("").replace("/files/dev.baldav.app", "")).join("baldav.db");
-    let db = if p1.exists() { p1 } else if p2.exists() { p2.clone() } else { p3 };
-    let root = data_dir.parent().and_then(|p| p.parent()).map(|p| p.to_path_buf()).unwrap_or(data_dir.clone());
+    let db = if p1.exists() { p1 } else if p2.exists() { p2 } else { p3 };
+    let root = db.parent().map(|p| p.to_path_buf()).unwrap_or(data_dir.clone());
     Ok((db, root))
 }