diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 583eedba97..eba1944f9e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -23,7 +23,9 @@ jobs:
            sudo apt-get update
            sudo apt-get install -y \
              ccache \
-             cxxtest
+             cxxtest \
+             protobuf-compiler \
+             libprotoc-dev
            python3 -m pip install --user --upgrade pip
            python3 -m pip install --user --upgrade setuptools
            python3 -m pip install --user wheel
diff --git a/src/engine/Preprocessor.cpp b/src/engine/Preprocessor.cpp
index 9c354941b3..fb1e4f5257 100644
--- a/src/engine/Preprocessor.cpp
+++ b/src/engine/Preprocessor.cpp
@@ -567,8 +567,8 @@ void Preprocessor::collectFixedValues()
 
     // Collect any variables with identical lower and upper bounds, or
     // which are unused
-	for ( unsigned i = 0; i < _preprocessed.getNumberOfVariables(); ++i )
-	{
+    for ( unsigned i = 0; i < _preprocessed.getNumberOfVariables(); ++i )
+    {
         if ( FloatUtils::areEqual( _preprocessed.getLowerBound( i ), _preprocessed.getUpperBound( i ) ) )
         {
             _fixedVariables[i] = _preprocessed.getLowerBound( i );