Try creating a zip and archiving it.

.gitlab-ci.yml

@@ -55,10 +55,11 @@ Win10:
     - env
     - sh %CI_PROJECT_DIR%/CI/before_script.msvc.sh -c Release -p x64 -v 2017 -V
     - SET msBuildLocation="C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\MSBuild\15.0\Bin\msbuild.exe"
-    - call %msBuildLocation% MSVC2017_64\OpenMW.sln /t:Build /p:Configuration=Release /m:%NUMBER_OF_PROCESSORS% 
+    - call %msBuildLocation% MSVC2017_64\OpenMW.sln /t:Build /p:Configuration=Release /m:%NUMBER_OF_PROCESSORS%
+    - 7z a OpenMW_MSVC2017_64_%CI_BUILD_REF_NAME%_%CI_BUILD_ID%.zip %CI_PROJECT_DIR%\MSVC2017_64\Release\ -xr"!*.pdb"
   cache:
     paths:
     - deps
   artifacts:
     paths:
-    - MSVC2017_64
+    - *.zip