diff --git a/ci/build.yml b/ci/build.yml
index 54e90b9a..e47d5c6c 100644
--- a/ci/build.yml
+++ b/ci/build.yml
@@ -1,5 +1,4 @@
 ---
-
 .script-build:
   stage: build
   needs: ["lint"]
@@ -22,6 +21,7 @@
       - bridge_*.tgz
       - vault-editor
       - bridge-rollout
+
 build-linux:
   extends:
     - .script-build
diff --git a/ci/env.yml b/ci/env.yml
index 3daa81a1..1d4c1b91 100644
--- a/ci/env.yml
+++ b/ci/env.yml
@@ -1,6 +1,4 @@
-
 ---
-
 .env-windows:
   extends:
     - .image-windows-virt-build
@@ -13,6 +11,12 @@
   variables:
     GOARCH: amd64
     BRIDGE_SYNC_FORCE_MINIMUM_SPEC: 1
+    VCPKG_DEFAULT_BINARY_CACHE: ${CI_PROJECT_DIR}/.cache
+  cache:
+    key: windows-vcpkg-go-1
+    paths:
+      - .cache
+    when: "always"
 
 .env-darwin:
   extends:
@@ -30,7 +34,7 @@
     key: darwin-go-and-vcpkg
     paths:
       - .cache
-    when: 'always'
+    when: "always"
 
 .env-linux-build:
   extends:
@@ -41,7 +45,7 @@
     key: linux-vcpkg
     paths:
       - .cache
-    when: 'always'
+    when: "always"
   before_script:
     - export BRIDGE_SYNC_FORCE_MINIMUM_SPEC=1
     - !reference [.before-script-git-config, before_script]
@@ -50,4 +54,3 @@
     - export GOPATH="$CI_PROJECT_DIR/.cache"
   tags:
     - shared-large
-
diff --git a/ci/setup.yml b/ci/setup.yml
index 087e7a76..3fee9618 100644
--- a/ci/setup.yml
+++ b/ci/setup.yml
@@ -1,7 +1,5 @@
 ---
-
 include:
-  - project: 'go/bridge-internal'
-    ref: 'master'
-    file: 'ci/runners-setup.yml'
-
+  - project: "go/bridge-internal"
+    ref: "master"
+    file: "ci/runners-setup.yml"
diff --git a/internal/frontend/bridge-gui/bridge-gui/build.ps1 b/internal/frontend/bridge-gui/bridge-gui/build.ps1
index f4b98afb..4a06bafb 100644
--- a/internal/frontend/bridge-gui/bridge-gui/build.ps1
+++ b/internal/frontend/bridge-gui/bridge-gui/build.ps1
@@ -15,8 +15,6 @@
 # You should have received a copy of the GNU General Public License
 # along with Proton Mail Bridge. If not, see <https://www.gnu.org/licenses/>.
 
-#!/bin/bash
-
 $scriptpath = $MyInvocation.MyCommand.Path
 $scriptDir = Split-Path $scriptpath
 $bridgeRepoRootDir = Join-Path $scriptDir "../../../.." -Resolve
@@ -24,6 +22,26 @@ Write-host "Bridge-gui directory is $scriptDir"
 Write-host "Bridge repos root dir $bridgeRepoRootDir"
 Push-Location $scriptDir
 
+# There is bug in CI caused by defining the lower case and upper case
+# vars for proxy. For pure bash (case sensitive - creating
+# two env items) or pure powershell (case insensitive - by default writes any
+# changes into first defined env instance) it is transparent. But during bridge gui
+# build we are populating case sensitive env vars from bash to powershell which
+# then cause error when trying to list env vars. This is causing an error
+# during CMake lookup for CXX and build fails. Therefore we need unset the
+# lower case version if present.
+Write-Host "Checking for duplicate proxy variables..."
+@("HTTP_PROXY", "HTTPS_PROXY", "NO_PROXY") | ForEach-Object {
+  $upper = $_
+  $lower = $_.ToLower()
+      
+  if ((Test-Path "Env:$upper") -and (Test-Path "Env:$lower")) {
+    Write-Host "Removing duplicate lowercase variable: $lower"
+    Remove-Item "Env:$lower" -ErrorAction SilentlyContinue
+  }
+}
+
+
 $ErrorActionPreference = "Stop"
 
 $cmakeExe=$(Get-Command cmake).source