diff --git a/coin/provisioning/common/unix/install_protobuf.sh b/coin/provisioning/common/unix/install_protobuf.sh
index bf3a6d90..9bb31c1f 100755
--- a/coin/provisioning/common/unix/install_protobuf.sh
+++ b/coin/provisioning/common/unix/install_protobuf.sh
@@ -92,7 +92,7 @@ cmake "$targetDir" -G"Ninja Multi-Config" \
 ninja all:all
 sudo env "PATH=$PATH" ninja install:all
 
-SetEnvVar "Protobuf_ROOT" "$installPrefix/lib/cmake/protobuf"
+SetEnvVar "protobuf_ROOT" "$installPrefix/lib/cmake/protobuf"
 
 # Refresh shared library cache if OS isn't macOS
 if uname -a |grep -qv "Darwin"; then