diff --git a/AppHandling/Compile-AppInNavContainer.ps1 b/AppHandling/Compile-AppInNavContainer.ps1
index 483f1cebd..0dfbb80ce 100644
--- a/AppHandling/Compile-AppInNavContainer.ps1
+++ b/AppHandling/Compile-AppInNavContainer.ps1
@@ -500,6 +500,7 @@ try {
                                 $alcPath = 'C:\build\vsix\extension\bin'
                                 Add-Type -Path (Join-Path $alcPath Newtonsoft.Json.dll)
                                 Add-Type -Path (Join-Path $alcPath System.Collections.Immutable.dll)
+                                Add-Type -Path (Join-Path $alcPath System.IO.Packaging.dll)
                                 Add-Type -Path (Join-Path $alcPath Microsoft.Dynamics.Nav.CodeAnalysis.dll)
 
                                 $packageStream = [System.IO.File]::OpenRead($symbolsFile)
diff --git a/HelperFunctions.ps1 b/HelperFunctions.ps1
index 30937837d..7052bced5 100644
--- a/HelperFunctions.ps1
+++ b/HelperFunctions.ps1
@@ -1147,6 +1147,7 @@ function GetAppInfo {
                     Add-Type -AssemblyName System.Text.Encoding
                     LoadDLL -Path (Join-Path $alcDllPath Newtonsoft.Json.dll)
                     LoadDLL -Path (Join-Path $alcDllPath System.Collections.Immutable.dll)
+		    LoadDLL -Path (Join-Path $alcDllPath System.IO.Packaging.dll)
                     LoadDLL -Path (Join-Path $alcDllPath Microsoft.Dynamics.Nav.CodeAnalysis.dll)
                     $assembliesAdded = $true
                 }
@@ -1247,4 +1248,4 @@ function DetermineVsixFile {
     else {
         return $vsixFile
     }
-}
\ No newline at end of file
+}