diff --git a/.github/workflows/windows-build.yml b/.github/workflows/windows-build.yml
index 555fe91..c0a9119 100644
--- a/.github/workflows/windows-build.yml
+++ b/.github/workflows/windows-build.yml
@@ -33,6 +33,9 @@ jobs:
       - name: Run build script
         run: src\BUILD_RELEASE.bat
 
+      - name: Verify build
+        run: if not exist release\dcef.exe exit 1
+
       - name: Upload build folder
         uses: actions/upload-artifact@v2
         with:
diff --git a/src/BUILD_RELEASE.bat b/src/BUILD_RELEASE.bat
index 0aeddc7..16e6531 100644
--- a/src/BUILD_RELEASE.bat
+++ b/src/BUILD_RELEASE.bat
@@ -27,10 +27,10 @@ mkdir "_temp"
 
 @REM install windows-runner dependencies
 if not exist "_temp\dcef\venv" (
-    py -m venv _temp\dcef\venv
+    call py -m venv _temp\dcef\venv
     call _temp\dcef\venv\Scripts\activate
-    pip install -r requirements.txt
-    deactivate
+    call pip install -r requirements.txt
+    call deactivate
 )
 @REM Build windows-runner
 py -m PyInstaller --onefile --name dcef       --icon "../../icon.ico"  --distpath "_temp/dcef/"       --specpath "_temp/dcef/"       --workpath "_temp/dcef/"       ./dcef.py  --paths "_temp\dcef\venv\Lib\site-packages"
@@ -41,10 +41,10 @@ move "_temp\dcef\dcef.exe" "..\release\dcef.exe"
 
 @REM install preprocess dependencies
 if not exist "_temp\preprocess\venv" (
-    py -m venv _temp\preprocess\venv
+    call py -m venv _temp\preprocess\venv
     call _temp\preprocess\venv\Scripts\activate
-    pip install -r dcef\backend\preprocess\requirements.txt
-    deactivate
+    call pip install -r dcef\backend\preprocess\requirements.txt
+    call deactivate
 )
 @REM Build preprocess
 py -m PyInstaller --onefile --name preprocess --icon "../../icon.ico"  --distpath "_temp/preprocess/" --specpath "_temp/preprocess/" --workpath "_temp/preprocess/" ./dcef/backend/preprocess/main_mongo.py --paths "_temp\preprocess\venv\Lib\site-packages"
@@ -56,10 +56,10 @@ copy "dcef\backend\preprocess\emojiIndex.json" "..\release\dcef\backend\preproce
 
 @REM install api-backend dependencies
 if not exist "_temp\fastapi\venv" (
-    py -m venv _temp\fastapi\venv
+    call py -m venv _temp\fastapi\venv
     call _temp\fastapi\venv\Scripts\activate
-    pip install -r dcef\backend\fastapi\requirements.txt
-    deactivate
+    call pip install -r dcef\backend\fastapi\requirements.txt
+    call deactivate
 )
 @REM build api-backend
 py -m PyInstaller --onefile --name fastapi    --icon "../../icon.ico"  --distpath "_temp/fastapi/"    --specpath "_temp/fastapi/"    --workpath "_temp/fastapi/"    ./dcef/backend/fastapi/prod.py           -F --hidden-import "uvicorn.logging" --hidden-import "uvicorn.loops" --hidden-import "uvicorn.loops.auto" --hidden-import "uvicorn.protocols" --hidden-import "uvicorn.protocols.http" --hidden-import "uvicorn.protocols.http.auto" --hidden-import "uvicorn.protocols.websockets" --hidden-import "uvicorn.protocols.websockets.auto" --hidden-import "uvicorn.lifespan" --hidden-import "uvicorn.lifespan.on" --hidden-import "src.main"  --paths "_temp\fastapi\venv\Lib\site-packages"
diff --git a/src/requirements.txt b/src/requirements.txt
index b8290e1..cbf5f28 100644
--- a/src/requirements.txt
+++ b/src/requirements.txt
@@ -1,3 +1,3 @@
 pywebview==4.0.1
-pywin32==305
+pywin32==306
 psutil==5.9.4
\ No newline at end of file