refactor: better tombstone handling

src-tauri/src/app_auto_updater.rs

@@ -704,7 +704,8 @@ impl AppAutoUpdater {
 
     let total_size = response.content_length().unwrap_or(0);
     log::info!("Silent download size: {} bytes", total_size);
-    let mut file = fs::File::create(&file_path)?;
+    let raw_file = fs::File::create(&file_path)?;
+    let mut file = std::io::BufWriter::with_capacity(8 * 1024 * 1024, raw_file);
     let mut stream = response.bytes_stream();
 
     use futures_util::StreamExt;
@@ -712,6 +713,7 @@ impl AppAutoUpdater {
       let chunk = chunk?;
       file.write_all(&chunk)?;
     }
+    std::io::Write::flush(&mut file)?;
 
     log::info!("Silent download completed: {}", file_path.display());
     Ok(file_path)

src-tauri/src/auto_updater.rs

@@ -145,6 +145,14 @@ impl AutoUpdater {
               let registry =
                 crate::downloaded_browsers_registry::DownloadedBrowsersRegistry::instance();
 
+              // Skip if this browser-version pair is already being downloaded
+              if crate::downloader::is_downloading(&browser, &new_version) {
+                log::info!(
+                  "Browser {browser} {new_version} is already being downloaded, skipping duplicate"
+                );
+                return;
+              }
+
               if registry.is_browser_downloaded(&browser, &new_version) {
                 log::info!("Browser {browser} {new_version} already downloaded, proceeding to auto-update profiles");
 

src-tauri/src/browser_runner.rs

@@ -2157,14 +2157,11 @@ impl BrowserRunner {
       .find(|p| p.id.to_string() == profile_id)
       .ok_or_else(|| format!("Profile '{profile_id}' not found"))?;
 
-    if profile.is_cross_os()
-      && !crate::cloud_auth::CLOUD_AUTH
-        .is_fingerprint_os_allowed(profile.host_os.as_deref())
-        .await
-    {
+    if profile.is_cross_os() {
       return Err(format!(
-        "Cannot open URL with profile '{}': cross-OS fingerprints require a paid subscription",
+        "Cannot open URL with profile '{}': this profile was created on {} and cannot be used on a different operating system",
         profile.name,
+        profile.host_os.as_deref().unwrap_or("another OS"),
       ));
     }
 
@@ -2196,14 +2193,11 @@ pub async fn launch_browser_profile(
     profile.id
   );
 
-  if profile.is_cross_os()
-    && !crate::cloud_auth::CLOUD_AUTH
-      .is_fingerprint_os_allowed(profile.host_os.as_deref())
-      .await
-  {
+  if profile.is_cross_os() {
     return Err(format!(
-      "Cannot launch profile '{}': cross-OS fingerprints require a paid subscription",
+      "Cannot launch profile '{}': this profile was created on {} and cannot be launched on a different operating system",
       profile.name,
+      profile.host_os.as_deref().unwrap_or("another OS"),
     ));
   }
 
@@ -2516,14 +2510,11 @@ pub async fn launch_browser_profile_with_debugging(
   remote_debugging_port: Option<u16>,
   headless: bool,
 ) -> Result<BrowserProfile, String> {
-  if profile.is_cross_os()
-    && !crate::cloud_auth::CLOUD_AUTH
-      .is_fingerprint_os_allowed(profile.host_os.as_deref())
-      .await
-  {
+  if profile.is_cross_os() {
     return Err(format!(
-      "Cannot launch profile '{}': cross-OS fingerprints require a paid subscription",
+      "Cannot launch profile '{}': this profile was created on {} and cannot be launched on a different operating system",
       profile.name,
+      profile.host_os.as_deref().unwrap_or("another OS"),
     ));
   }
 

src-tauri/src/downloader.rs

@@ -445,12 +445,16 @@ impl Downloader {
 
     let _ = events::emit("download-progress", &progress);
 
-    // Open file in append mode (resuming) or create new
+    // Open file in append mode (resuming) or create new.
+    // Wrap in BufWriter with a large buffer to reduce the number of disk writes,
+    // which dramatically improves download speed on Windows (NTFS + Defender overhead).
     use std::fs::OpenOptions;
-    let mut file = OpenOptions::new()
+    use std::io::Write;
+    let raw_file = OpenOptions::new()
       .create(true)
       .append(true)
       .open(&file_path)?;
+    let mut file = io::BufWriter::with_capacity(8 * 1024 * 1024, raw_file);
     let mut stream = response.bytes_stream();
 
     use futures_util::StreamExt;
@@ -463,7 +467,7 @@ impl Downloader {
         }
       }
       let chunk = chunk?;
-      io::copy(&mut chunk.as_ref(), &mut file)?;
+      file.write_all(&chunk)?;
       downloaded += chunk.len() as u64;
 
       let now = std::time::Instant::now();
@@ -510,6 +514,9 @@ impl Downloader {
       }
     }
 
+    // Flush remaining buffered data to disk
+    file.flush()?;
+
     Ok(file_path)
   }
 
@@ -953,6 +960,13 @@ impl Downloader {
   }
 }
 
+/// Check if a specific browser-version pair is currently being downloaded
+pub fn is_downloading(browser: &str, version: &str) -> bool {
+  let download_key = format!("{browser}-{version}");
+  let downloading = DOWNLOADING_BROWSERS.lock().unwrap();
+  downloading.contains(&download_key)
+}
+
 #[tauri::command]
 pub async fn download_browser(
   app_handle: tauri::AppHandle,

src-tauri/src/profile/manager.rs

@@ -425,8 +425,21 @@ impl ProfileManager {
       if path.is_dir() {
         let metadata_file = path.join("metadata.json");
         if metadata_file.exists() {
-          let content = fs::read_to_string(metadata_file)?;
-          let profile: BrowserProfile = serde_json::from_str(&content)?;
+          let content = fs::read_to_string(&metadata_file)?;
+          let mut profile: BrowserProfile = serde_json::from_str(&content)?;
+
+          // Backfill host_os from browser config for profiles created before
+          // the field existed (or synced without it).
+          if profile.host_os.is_none() {
+            let inferred_os = profile.resolved_os().map(str::to_string);
+            if let Some(os) = inferred_os {
+              profile.host_os = Some(os);
+              if let Ok(json) = serde_json::to_string_pretty(&profile) {
+                let _ = fs::write(&metadata_file, json);
+              }
+            }
+          }
+
           profiles.push(profile);
         }
       }
@@ -566,6 +579,29 @@ impl ProfileManager {
     Ok(())
   }
 
+  /// Delete a profile from the local filesystem only, without triggering remote sync deletion.
+  /// Used when a profile was deleted on another device and the local copy should be cleaned up.
+  pub fn delete_profile_local_only(
+    &self,
+    profile_id: &str,
+  ) -> Result<(), Box<dyn std::error::Error>> {
+    let profiles_dir = self.get_profiles_dir();
+    let profile_dir = profiles_dir.join(profile_id);
+    if profile_dir.exists() {
+      fs::remove_dir_all(&profile_dir)?;
+      log::info!("Deleted local profile {} (tombstoned remotely)", profile_id);
+    }
+
+    if let Err(e) = crate::downloaded_browsers_registry::DownloadedBrowsersRegistry::instance()
+      .cleanup_unused_binaries()
+    {
+      log::warn!("Failed to cleanup binaries after tombstone deletion: {e}");
+    }
+
+    let _ = crate::events::emit_empty("profiles-changed");
+    Ok(())
+  }
+
   pub fn update_profile_version(
     &self,
     _app_handle: &tauri::AppHandle,

src-tauri/src/profile/types.rs

@@ -87,11 +87,22 @@ impl BrowserProfile {
     profiles_dir.join(self.id.to_string()).join("profile")
   }
 
+  /// Resolve the OS this profile was created on. Checks `host_os` first,
+  /// then falls back to the fingerprint config's `os` field (for profiles
+  /// created before `host_os` was introduced or synced without it).
+  pub fn resolved_os(&self) -> Option<&str> {
+    self
+      .host_os
+      .as_deref()
+      .or_else(|| self.camoufox_config.as_ref().and_then(|c| c.os.as_deref()))
+      .or_else(|| self.wayfern_config.as_ref().and_then(|c| c.os.as_deref()))
+  }
+
   /// Returns true when the profile was created on a different OS than the current host.
-  /// Profiles without an `os` field (backward compat) are treated as native.
+  /// Checks `host_os` first, then falls back to the browser config's `os` field.
   pub fn is_cross_os(&self) -> bool {
-    match &self.host_os {
-      Some(host_os) => host_os != &get_host_os(),
+    match self.resolved_os() {
+      Some(os) => os != get_host_os(),
       None => false,
     }
   }

src-tauri/src/profile_importer.rs

@@ -1035,7 +1035,9 @@ Path=test.profile
   fn test_get_default_version_for_browser_no_versions() {
     let (importer, _temp_dir) = create_test_profile_importer();
 
-    let result = importer.get_default_version_for_browser("camoufox");
+    // Use a browser name that is guaranteed to have no downloaded versions,
+    // since the global registry singleton may contain real data from the system.
+    let result = importer.get_default_version_for_browser("nonexistent_browser_xyz");
     assert!(
       result.is_err(),
       "Should fail when no versions are available"

src-tauri/src/proxy_manager.rs

@@ -2741,17 +2741,19 @@ mod tests {
   fn test_process_running_detection_with_child_lifecycle() {
     use crate::proxy_storage::is_process_running;
 
-    // Spawn a long-lived child so we can check while it runs
-    let mut child = std::process::Command::new(if cfg!(windows) { "timeout" } else { "sleep" })
+    // Spawn a long-lived child so we can check while it runs.
+    // On Windows, `timeout` requires console input and exits immediately in
+    // non-interactive contexts, so use `ping` with a high count instead.
+    let mut child = std::process::Command::new(if cfg!(windows) { "ping" } else { "sleep" })
       .args(if cfg!(windows) {
-        vec!["/T", "10"]
+        vec!["-n", "100", "127.0.0.1"]
       } else {
         vec!["10"]
       })
       .stdout(std::process::Stdio::null())
       .stderr(std::process::Stdio::null())
       .spawn()
-      .expect("spawn sleep");
+      .expect("spawn long-lived child");
 
     let pid = child.id();
 

src-tauri/src/sync/engine.rs

@@ -2361,6 +2361,54 @@ impl SyncEngine {
       log::info!("No missing profiles found");
     }
 
+    // Delete local synced profiles that have a remote tombstone (deleted on another device)
+    {
+      let profile_manager = ProfileManager::instance();
+      let local_synced: Vec<(String, Option<String>)> = profile_manager
+        .list_profiles()
+        .unwrap_or_default()
+        .iter()
+        .filter(|p| p.is_sync_enabled())
+        .map(|p| (p.id.to_string(), p.created_by_id.clone()))
+        .collect();
+
+      let team_prefix = if let Some(auth) = crate::cloud_auth::CLOUD_AUTH.get_user().await {
+        auth.user.team_id.map(|tid| format!("teams/{}/", tid))
+      } else {
+        None
+      };
+
+      for (pid, created_by_id) in &local_synced {
+        // Check personal tombstone
+        let personal_tombstone = format!("tombstones/profiles/{}.json", pid);
+        let has_personal_tombstone = matches!(
+          self.client.stat(&personal_tombstone).await,
+          Ok(stat) if stat.exists
+        );
+
+        // Check team tombstone
+        let has_team_tombstone = if let (Some(tp), Some(_)) = (&team_prefix, created_by_id) {
+          let team_tombstone = format!("{}tombstones/profiles/{}.json", tp, pid);
+          matches!(
+            self.client.stat(&team_tombstone).await,
+            Ok(stat) if stat.exists
+          )
+        } else {
+          false
+        };
+
+        if has_personal_tombstone || has_team_tombstone {
+          log::info!(
+            "Profile {} has remote tombstone, deleting locally (deleted on another device)",
+            pid
+          );
+          if let Err(e) = profile_manager.delete_profile_local_only(pid) {
+            log::warn!("Failed to delete tombstoned profile {}: {}", pid, e);
+          }
+        }
+      }
+    }
+
     // Refresh metadata for local cross-OS profiles (propagate renames, tags, notes from originating device)
     let profile_manager = ProfileManager::instance();
     // Collect cross-OS profiles before async operations to avoid holding non-Send Result across await