diff --git a/apps/desktop/desktop_native/Cargo.lock b/apps/desktop/desktop_native/Cargo.lock
index 5ceaf08016b..4182de59382 100644
--- a/apps/desktop/desktop_native/Cargo.lock
+++ b/apps/desktop/desktop_native/Cargo.lock
@@ -1024,7 +1024,6 @@ dependencies = [
  "widestring",
  "windows 0.62.2",
  "windows-future 0.3.2",
- "windows_plugin_authenticator",
  "zbus",
  "zbus_polkit",
  "zeroizing-alloc",
diff --git a/apps/desktop/desktop_native/core/Cargo.toml b/apps/desktop/desktop_native/core/Cargo.toml
index d13244db6a2..6e7ad240144 100644
--- a/apps/desktop/desktop_native/core/Cargo.toml
+++ b/apps/desktop/desktop_native/core/Cargo.toml
@@ -69,13 +69,14 @@ windows = { workspace = true, features = [
     "Win32_Foundation",
     "Win32_Security_Credentials",
     "Win32_Security_Cryptography",
+    "Win32_System_Com",
+    "Win32_System_LibraryLoader",
     "Win32_System_WinRT",
     "Win32_UI_Input_KeyboardAndMouse",
     "Win32_UI_WindowsAndMessaging",
     "Win32_System_Pipes",
 ], optional = true }
 windows-future = { workspace = true }
-windows_plugin_authenticator = { path = "../windows_plugin_authenticator" }
 
 [target.'cfg(windows)'.dev-dependencies]
 keytar = { workspace = true }
diff --git a/apps/desktop/desktop_native/core/src/autofill/windows.rs b/apps/desktop/desktop_native/core/src/autofill/windows.rs
index fffafd06d10..aa1a0bae4c7 100644
--- a/apps/desktop/desktop_native/core/src/autofill/windows.rs
+++ b/apps/desktop/desktop_native/core/src/autofill/windows.rs
@@ -1,6 +1,15 @@
+use std::alloc;
+use std::mem::{align_of, MaybeUninit};
+use std::ptr::NonNull;
+
 use anyhow::{anyhow, Result};
 use base64::engine::{general_purpose::URL_SAFE_NO_PAD, Engine};
-use windows_plugin_authenticator::{self, SyncedCredential};
+use windows::core::s;
+use windows::Win32::Foundation::FreeLibrary;
+use windows::{
+    core::{GUID, HRESULT, PCSTR},
+    Win32::System::{Com::CoTaskMemAlloc, LibraryLoader::*},
+};
 
 use crate::autofill::{
     CommandResponse, RunCommand, RunCommandRequest, StatusResponse, StatusState, StatusSupport,
@@ -66,7 +75,7 @@ fn handle_sync_request(params: SyncParameters) -> Result<SyncResponse> {
         .filter_map(|c| c.try_into().ok())
         .collect();
     let num_creds = credentials.len().try_into().unwrap_or(u32::MAX);
-    windows_plugin_authenticator::sync_credentials_to_windows(credentials, PLUGIN_CLSID)
+    sync_credentials_to_windows(credentials, PLUGIN_CLSID)
         .map_err(|e| anyhow!("Failed to sync credentials to Windows: {e}"))?;
     Ok(SyncResponse { added: num_creds })
     /*
@@ -247,3 +256,370 @@ impl TryFrom<SyncCredential> for SyncedCredential {
         }
     }
 }
+
+/// Initiates credential sync from Electron to Windows - called when Electron wants to push credentials to Windows
+fn sync_credentials_to_windows(
+    credentials: Vec<SyncedCredential>,
+    plugin_clsid: &str,
+) -> Result<(), String> {
+    tracing::debug!(
+        "[SYNC_TO_WIN] sync_credentials_to_windows called with {} credentials for plugin CLSID: {}",
+        credentials.len(),
+        plugin_clsid
+    );
+
+    // Parse CLSID string to GUID
+    let clsid_guid = parse_clsid_to_guid_str(plugin_clsid)
+        .map_err(|e| format!("Failed to parse CLSID: {}", e))?;
+
+    if credentials.is_empty() {
+        tracing::debug!("[SYNC_TO_WIN] No credentials to sync, proceeding with empty sync");
+    }
+
+    // Convert Bitwarden credentials to Windows credential details
+    let mut win_credentials = Vec::new();
+
+    for (i, cred) in credentials.iter().enumerate() {
+        tracing::debug!("[SYNC_TO_WIN] Converting credential {}: RP ID: {}, User: {}, Credential ID: {:?} ({} bytes), User ID: {:?} ({} bytes)",
+            i + 1, cred.rp_id, cred.user_name, &cred.credential_id, cred.credential_id.len(), &cred.user_handle, cred.user_handle.len());
+
+        let win_cred = WebAuthnPluginCredentialDetails::create_from_bytes(
+            cred.credential_id.clone(), // Pass raw bytes
+            cred.rp_id.clone(),
+            cred.rp_id.clone(),       // Use RP ID as friendly name for now
+            cred.user_handle.clone(), // Pass raw bytes
+            cred.user_name.clone(),
+            cred.user_name.clone(), // Use user name as display name for now
+        );
+
+        win_credentials.push(win_cred);
+        tracing::debug!(
+            "[SYNC_TO_WIN] Converted credential {} to Windows format",
+            i + 1
+        );
+    }
+
+    // First try to remove all existing credentials for this plugin
+    tracing::debug!("Attempting to remove all existing credentials before sync...");
+    match remove_all_credentials(clsid_guid) {
+        Ok(()) => {
+            tracing::debug!("Successfully removed existing credentials");
+        }
+        Err(e) if e.contains("can't be loaded") => {
+            tracing::debug!("RemoveAllCredentials function not available - this is expected for some Windows versions");
+            // This is fine, the function might not exist in all versions
+        }
+        Err(e) => {
+            tracing::debug!("Warning: Failed to remove existing credentials: {}", e);
+            // Continue anyway, as this might be the first sync or an older Windows version
+        }
+    }
+
+    // Add the new credentials (only if we have any)
+    if credentials.is_empty() {
+        tracing::debug!("No credentials to add to Windows - sync completed successfully");
+        Ok(())
+    } else {
+        tracing::debug!("Adding new credentials to Windows...");
+        match add_credentials(clsid_guid, win_credentials) {
+            Ok(()) => {
+                tracing::debug!("Successfully synced credentials to Windows");
+                Ok(())
+            }
+            Err(e) => {
+                tracing::debug!("ERROR: Failed to add credentials to Windows: {}", e);
+                Err(e)
+            }
+        }
+    }
+}
+
+/// Credential data for sync operations
+#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
+#[serde(rename_all = "camelCase")]
+struct SyncedCredential {
+    pub credential_id: Vec<u8>,
+    pub rp_id: String,
+    pub user_name: String,
+    pub user_handle: Vec<u8>,
+}
+
+/// Represents a credential.
+/// Header File Name: _WEBAUTHN_PLUGIN_CREDENTIAL_DETAILS
+/// Header File Usage: WebAuthNPluginAuthenticatorAddCredentials, etc.
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+struct WebAuthnPluginCredentialDetails {
+    pub credential_id_byte_count: u32,
+    pub credential_id_pointer: *const u8, // Changed to const in stable
+    pub rpid: *const u16,                 // Changed to const (LPCWSTR)
+    pub rp_friendly_name: *const u16,     // Changed to const (LPCWSTR)
+    pub user_id_byte_count: u32,
+    pub user_id_pointer: *const u8,    // Changed to const
+    pub user_name: *const u16,         // Changed to const (LPCWSTR)
+    pub user_display_name: *const u16, // Changed to const (LPCWSTR)
+}
+
+impl WebAuthnPluginCredentialDetails {
+    pub fn create_from_bytes(
+        credential_id: Vec<u8>,
+        rpid: String,
+        rp_friendly_name: String,
+        user_id: Vec<u8>,
+        user_name: String,
+        user_display_name: String,
+    ) -> Self {
+        // Allocate credential_id bytes with COM
+        let (credential_id_pointer, credential_id_byte_count) =
+            ComBuffer::from_buffer(&credential_id);
+
+        // Allocate user_id bytes with COM
+        let (user_id_pointer, user_id_byte_count) = ComBuffer::from_buffer(&user_id);
+
+        // Convert strings to null-terminated wide strings using trait methods
+        let (rpid_ptr, _) = rpid.to_com_utf16();
+        let (rp_friendly_name_ptr, _) = rp_friendly_name.to_com_utf16();
+        let (user_name_ptr, _) = user_name.to_com_utf16();
+        let (user_display_name_ptr, _) = user_display_name.to_com_utf16();
+
+        Self {
+            credential_id_byte_count,
+            credential_id_pointer: credential_id_pointer as *const u8,
+            rpid: rpid_ptr as *const u16,
+            rp_friendly_name: rp_friendly_name_ptr as *const u16,
+            user_id_byte_count,
+            user_id_pointer: user_id_pointer as *const u8,
+            user_name: user_name_ptr as *const u16,
+            user_display_name: user_display_name_ptr as *const u16,
+        }
+    }
+}
+
+// Stable API function signatures - now use REFCLSID and flat arrays
+type WebAuthNPluginAuthenticatorAddCredentialsFnDeclaration = unsafe extern "cdecl" fn(
+    rclsid: *const GUID, // Changed from string to GUID reference
+    cCredentialDetails: u32,
+    pCredentialDetails: *const WebAuthnPluginCredentialDetails, // Flat array, not list
+) -> HRESULT;
+
+/// Trait for converting strings to Windows-compatible wide strings using COM allocation
+pub trait WindowsString {
+    /// Converts to null-terminated UTF-16 using COM allocation
+    fn to_com_utf16(&self) -> (*mut u16, u32);
+    /// Converts to Vec<u16> for temporary use (caller must keep Vec alive)
+    fn to_utf16(&self) -> Vec<u16>;
+}
+
+impl WindowsString for str {
+    fn to_com_utf16(&self) -> (*mut u16, u32) {
+        let mut wide_vec: Vec<u16> = self.encode_utf16().collect();
+        wide_vec.push(0); // null terminator
+        let wide_bytes: Vec<u8> = wide_vec.iter().flat_map(|&x| x.to_le_bytes()).collect();
+        let (ptr, byte_count) = ComBuffer::from_buffer(&wide_bytes);
+        (ptr as *mut u16, byte_count)
+    }
+
+    fn to_utf16(&self) -> Vec<u16> {
+        let mut wide_vec: Vec<u16> = self.encode_utf16().collect();
+        wide_vec.push(0); // null terminator
+        wide_vec
+    }
+}
+
+#[repr(transparent)]
+pub struct ComBuffer(NonNull<MaybeUninit<u8>>);
+
+impl ComBuffer {
+    /// Returns an COM-allocated buffer of `size`.
+    fn alloc(size: usize, for_slice: bool) -> Self {
+        #[expect(clippy::as_conversions)]
+        {
+            assert!(size <= isize::MAX as usize, "requested bad object size");
+        }
+
+        // SAFETY: Any size is valid to pass to Windows, even `0`.
+        let ptr = NonNull::new(unsafe { CoTaskMemAlloc(size) }).unwrap_or_else(|| {
+            // XXX: This doesn't have to be correct, just close enough for an OK OOM error.
+            let layout = alloc::Layout::from_size_align(size, align_of::<u8>()).unwrap();
+            alloc::handle_alloc_error(layout)
+        });
+
+        if for_slice {
+            // Ininitialize the buffer so it can later be treated as `&mut [u8]`.
+            // SAFETY: The pointer is valid and we are using a valid value for a byte-wise allocation.
+            unsafe { ptr.write_bytes(0, size) };
+        }
+
+        Self(ptr.cast())
+    }
+
+    fn into_ptr<T>(self) -> *mut T {
+        self.0.cast().as_ptr()
+    }
+
+    /// Creates a new COM-allocated structure.
+    ///
+    /// Note that `T` must be [Copy] to avoid any possible memory leaks.
+    pub fn with_object<T: Copy>(object: T) -> *mut T {
+        // NB: Vendored from Rust's alloc code since we can't yet allocate `Box` with a custom allocator.
+        const MIN_ALIGN: usize = if cfg!(target_pointer_width = "64") {
+            16
+        } else if cfg!(target_pointer_width = "32") {
+            8
+        } else {
+            panic!("unsupported arch")
+        };
+
+        // SAFETY: Validate that our alignment works for a normal size-based allocation for soundness.
+        let layout = const {
+            let layout = alloc::Layout::new::<T>();
+            assert!(layout.align() <= MIN_ALIGN);
+            layout
+        };
+
+        let buffer = Self::alloc(layout.size(), false);
+        // SAFETY: `ptr` is valid for writes of `T` because we correctly allocated the right sized buffer that
+        // accounts for any alignment requirements.
+        //
+        // Additionally, we ensure the value is treated as moved by forgetting the source.
+        unsafe { buffer.0.cast::<T>().write(object) };
+        buffer.into_ptr()
+    }
+
+    pub fn from_buffer<T: AsRef<[u8]>>(buffer: T) -> (*mut u8, u32) {
+        let buffer = buffer.as_ref();
+        let len = buffer.len();
+        let com_buffer = Self::alloc(len, true);
+
+        // SAFETY: `ptr` points to a valid allocation that `len` matches, and we made sure
+        // the bytes were initialized. Additionally, bytes have no alignment requirements.
+        unsafe {
+            NonNull::slice_from_raw_parts(com_buffer.0.cast::<u8>(), len)
+                .as_mut()
+                .copy_from_slice(buffer)
+        }
+
+        // Safety: The Windows API structures these buffers are placed into use `u32` (`DWORD`) to
+        // represent length.
+        #[expect(clippy::as_conversions)]
+        (com_buffer.into_ptr(), len as u32)
+    }
+}
+
+/// Converts a CLSID string to a GUID
+pub(crate) fn parse_clsid_to_guid_str(clsid_str: &str) -> Result<GUID, String> {
+    // Remove hyphens and parse as hex
+    let clsid_clean = clsid_str.replace("-", "");
+    if clsid_clean.len() != 32 {
+        return Err("Invalid CLSID format".to_string());
+    }
+
+    // Convert to u128 and create GUID
+    let clsid_u128 = u128::from_str_radix(&clsid_clean, 16)
+        .map_err(|_| "Failed to parse CLSID as hex".to_string())?;
+
+    Ok(GUID::from_u128(clsid_u128))
+}
+
+pub fn remove_all_credentials(clsid_guid: GUID) -> std::result::Result<(), String> {
+    tracing::debug!("Loading WebAuthNPluginAuthenticatorRemoveAllCredentials function...");
+
+    let result = unsafe {
+        delay_load::<WebAuthNPluginAuthenticatorRemoveAllCredentialsFnDeclaration>(
+            s!("webauthn.dll"),
+            s!("WebAuthNPluginAuthenticatorRemoveAllCredentials"),
+        )
+    };
+
+    match result {
+        Some(api) => {
+            tracing::debug!("Function loaded successfully, calling API...");
+
+            let result = unsafe { api(&clsid_guid) };
+
+            if result.is_err() {
+                let error_code = result.0;
+                tracing::debug!("API call failed with HRESULT: 0x{:x}", error_code);
+
+                return Err(format!(
+                    "Error: Error response from WebAuthNPluginAuthenticatorRemoveAllCredentials()\nHRESULT: 0x{:x}\n{}",
+                    error_code, result.message()
+                ));
+            }
+
+            tracing::debug!("API call succeeded");
+            Ok(())
+        }
+        None => {
+            tracing::debug!("Failed to load WebAuthNPluginAuthenticatorRemoveAllCredentials function from webauthn.dll");
+            Err(String::from("Error: Can't complete remove_all_credentials(), as the function WebAuthNPluginAuthenticatorRemoveAllCredentials can't be loaded."))
+        }
+    }
+}
+
+pub unsafe fn delay_load<T>(library: PCSTR, function: PCSTR) -> Option<T> {
+    let library = LoadLibraryExA(library, None, LOAD_LIBRARY_SEARCH_DEFAULT_DIRS);
+
+    let Ok(library) = library else {
+        return None;
+    };
+
+    let address = GetProcAddress(library, function);
+
+    if address.is_some() {
+        return Some(std::mem::transmute_copy(&address));
+    }
+
+    _ = FreeLibrary(library);
+
+    None
+}
+
+fn add_credentials(
+    clsid_guid: GUID,
+    credentials: Vec<WebAuthnPluginCredentialDetails>,
+) -> std::result::Result<(), String> {
+    tracing::debug!("Loading WebAuthNPluginAuthenticatorAddCredentials function...");
+
+    let result = unsafe {
+        delay_load::<WebAuthNPluginAuthenticatorAddCredentialsFnDeclaration>(
+            s!("webauthn.dll"),
+            s!("WebAuthNPluginAuthenticatorAddCredentials"),
+        )
+    };
+
+    match result {
+        Some(api) => {
+            tracing::debug!("Function loaded successfully, calling API...");
+            tracing::debug!("Adding {} credentials", credentials.len());
+
+            let credential_count = credentials.len() as u32;
+            let credentials_ptr = if credentials.is_empty() {
+                std::ptr::null()
+            } else {
+                credentials.as_ptr()
+            };
+
+            let result = unsafe { api(&clsid_guid, credential_count, credentials_ptr) };
+
+            if result.is_err() {
+                let error_code = result.0;
+                tracing::debug!("API call failed with HRESULT: 0x{:x}", error_code);
+                return Err(format!(
+                    "Error: Error response from WebAuthNPluginAuthenticatorAddCredentials()\nHRESULT: 0x{:x}\n{}",
+                    error_code, result.message()
+                ));
+            }
+
+            tracing::debug!("API call succeeded");
+            Ok(())
+        }
+        None => {
+            tracing::debug!("Failed to load WebAuthNPluginAuthenticatorAddCredentials function from webauthn.dll");
+            Err(String::from("Error: Can't complete add_credentials(), as the function WebAuthNPluginAuthenticatorAddCredentials can't be loaded."))
+        }
+    }
+}
+
+type WebAuthNPluginAuthenticatorRemoveAllCredentialsFnDeclaration =
+    unsafe extern "cdecl" fn(rclsid: *const GUID) -> HRESULT;