diff --git a/openless-all/app/package-lock.json b/openless-all/app/package-lock.json
index 4f9b7c9f..9c599b80 100644
--- a/openless-all/app/package-lock.json
+++ b/openless-all/app/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "openless-app",
-  "version": "1.2.24-4",
+  "version": "1.2.24-5",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "openless-app",
-      "version": "1.2.24-4",
+      "version": "1.2.24-5",
       "dependencies": {
         "@tauri-apps/api": "^2.1.1",
         "@tauri-apps/plugin-autostart": "^2.5.1",
diff --git a/openless-all/app/package.json b/openless-all/app/package.json
index 4f2e75f4..258d20fa 100644
--- a/openless-all/app/package.json
+++ b/openless-all/app/package.json
@@ -1,7 +1,7 @@
 {
   "name": "openless-app",
   "private": true,
-  "version": "1.2.24-4",
+  "version": "1.2.24-5",
   "type": "module",
   "scripts": {
     "dev": "vite",
diff --git a/openless-all/app/src-tauri/Cargo.lock b/openless-all/app/src-tauri/Cargo.lock
index 8b9aaf09..e1283ab8 100644
--- a/openless-all/app/src-tauri/Cargo.lock
+++ b/openless-all/app/src-tauri/Cargo.lock
@@ -3751,7 +3751,7 @@ dependencies = [
 
 [[package]]
 name = "openless"
-version = "1.2.24-4"
+version = "1.2.24-5"
 dependencies = [
  "anyhow",
  "arboard",
diff --git a/openless-all/app/src-tauri/Cargo.toml b/openless-all/app/src-tauri/Cargo.toml
index ec2d958f..eead6568 100644
--- a/openless-all/app/src-tauri/Cargo.toml
+++ b/openless-all/app/src-tauri/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "openless"
-version = "1.2.24-4"
+version = "1.2.24-5"
 description = "OpenLess — local voice input that types where your cursor is"
 authors = ["OpenLess"]
 edition = "2021"
diff --git a/openless-all/app/src-tauri/nsis/openless-ime-hooks.nsh b/openless-all/app/src-tauri/nsis/openless-ime-hooks.nsh
index 34e7ab1d..cdf6c9ff 100644
--- a/openless-all/app/src-tauri/nsis/openless-ime-hooks.nsh
+++ b/openless-all/app/src-tauri/nsis/openless-ime-hooks.nsh
@@ -56,12 +56,34 @@
   !insertmacro OPENLESS_IME_ABORT_IF_FAILED $0 "x86 registration"
 !macroend
 
-!macro NSIS_HOOK_PREINSTALL
-  SetOutPath "$INSTDIR\windows-ime\x64"
-  File /oname=OpenLessIme.dll "$%OPENLESS_IME_DLL_X64%"
+!macro OPENLESS_IME_STAGE_AND_REPLACE PLATFORM_DIR ENV_VAR
+  ; Write new bytes to OpenLessIme.dll.new, then atomically replace the old file.
+  ; If the old DLL is still mapped into TSF client processes (browsers, IDEs,
+  ; chat apps, ...) and Delete fails, queue the rename for next reboot via
+  ; PendingFileRenameOperations. Issue #321.
+  SetOutPath "$INSTDIR\windows-ime\${PLATFORM_DIR}"
+  File /oname=OpenLessIme.dll.new "$%${ENV_VAR}%"
+  ClearErrors
+  Delete "$INSTDIR\windows-ime\${PLATFORM_DIR}\OpenLessIme.dll"
+  ${If} ${Errors}
+    DetailPrint "OpenLessIme.dll (${PLATFORM_DIR}) is in use; queuing replacement at next reboot"
+    Rename /REBOOTOK "$INSTDIR\windows-ime\${PLATFORM_DIR}\OpenLessIme.dll.new" "$INSTDIR\windows-ime\${PLATFORM_DIR}\OpenLessIme.dll"
+    SetRebootFlag true
+  ${Else}
+    Rename "$INSTDIR\windows-ime\${PLATFORM_DIR}\OpenLessIme.dll.new" "$INSTDIR\windows-ime\${PLATFORM_DIR}\OpenLessIme.dll"
+  ${EndIf}
+!macroend
 
-  SetOutPath "$INSTDIR\windows-ime\x86"
-  File /oname=OpenLessIme.dll "$%OPENLESS_IME_DLL_X86%"
+!macro NSIS_HOOK_PREINSTALL
+  ; Upgrade path: release the COM/TSF registration so new client processes won't
+  ; bind to the old DLL while we replace it. Fresh install: regsvr32 /u against
+  ; a missing DLL is harmless — the existing UNREGISTER macros log the exit code
+  ; and continue without aborting.
+  !insertmacro OPENLESS_IME_UNREGISTER_X86
+  !insertmacro OPENLESS_IME_UNREGISTER_X64
+
+  !insertmacro OPENLESS_IME_STAGE_AND_REPLACE "x64" "OPENLESS_IME_DLL_X64"
+  !insertmacro OPENLESS_IME_STAGE_AND_REPLACE "x86" "OPENLESS_IME_DLL_X86"
 
   SetOutPath "$INSTDIR"
 !macroend
diff --git a/openless-all/app/src-tauri/tauri.conf.json b/openless-all/app/src-tauri/tauri.conf.json
index cf2fa44a..0c7c2300 100644
--- a/openless-all/app/src-tauri/tauri.conf.json
+++ b/openless-all/app/src-tauri/tauri.conf.json
@@ -1,7 +1,7 @@
 {
   "$schema": "https://schema.tauri.app/config/2",
   "productName": "OpenLess",
-  "version": "1.2.24-4",
+  "version": "1.2.24-5",
   "identifier": "com.openless.app",
   "build": {
     "beforeDevCommand": "npm run dev",
diff --git a/openless-all/app/src-tauri/wix/openless-ime.wxs b/openless-all/app/src-tauri/wix/openless-ime.wxs
index f7571a1b..39e419e2 100644
--- a/openless-all/app/src-tauri/wix/openless-ime.wxs
+++ b/openless-all/app/src-tauri/wix/openless-ime.wxs
@@ -45,8 +45,13 @@
       Return="ignore" />
 
     <InstallExecuteSequence>
-      <Custom Action="UnregisterOpenLessImeX86" Before="RemoveFiles"><![CDATA[REMOVE="ALL"]]></Custom>
-      <Custom Action="UnregisterOpenLessImeX64" Before="UnregisterOpenLessImeX86"><![CDATA[REMOVE="ALL"]]></Custom>
+      <!-- Issue #321: unregister the old DLL before InstallFiles whenever a
+           previous version is installed, so Windows Installer can overwrite
+           OpenLessIme.dll instead of failing on a sharing violation. The
+           previous condition (REMOVE="ALL") only fired during dedicated
+           uninstall and skipped the auto-update / minor-upgrade path. -->
+      <Custom Action="UnregisterOpenLessImeX86" Before="InstallFiles"><![CDATA[Installed AND NOT REMOVE]]></Custom>
+      <Custom Action="UnregisterOpenLessImeX64" Before="UnregisterOpenLessImeX86"><![CDATA[Installed AND NOT REMOVE]]></Custom>
       <Custom Action="RegisterOpenLessImeX64" After="InstallFiles"><![CDATA[NOT REMOVE]]></Custom>
       <Custom Action="RegisterOpenLessImeX86" After="RegisterOpenLessImeX64"><![CDATA[NOT REMOVE]]></Custom>
     </InstallExecuteSequence>