diff --git a/core/org.eclipse.statet.rj.server/src/org/eclipse/statet/rj/server/util/LocalREnv.java b/core/org.eclipse.statet.rj.server/src/org/eclipse/statet/rj/server/util/LocalREnv.java
index e1c16df..04f7b87 100644
--- a/core/org.eclipse.statet.rj.server/src/org/eclipse/statet/rj/server/util/LocalREnv.java
+++ b/core/org.eclipse.statet.rj.server/src/org/eclipse/statet/rj/server/util/LocalREnv.java
@@ -21,6 +21,7 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import java.util.Locale;
 import java.util.function.Function;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -43,7 +44,7 @@
 	
 	private static final int OS_TYPE;
 	static {
-		final String osname= System.getProperty("os.name").toLowerCase(); //$NON-NLS-1$
+		final String osname= System.getProperty("os.name").toLowerCase(Locale.ROOT); //$NON-NLS-1$
 		if (osname.contains("win")) { //$NON-NLS-1$
 			OS_TYPE= OS_WIN;
 		}
diff --git a/core/org.eclipse.statet.rj.services.core/srcEnv/org/eclipse/statet/rj/renv/core/RPkgUtils.java b/core/org.eclipse.statet.rj.services.core/srcEnv/org/eclipse/statet/rj/renv/core/RPkgUtils.java
index 9b9ba0d..06e43c5 100644
--- a/core/org.eclipse.statet.rj.services.core/srcEnv/org/eclipse/statet/rj/renv/core/RPkgUtils.java
+++ b/core/org.eclipse.statet.rj.services.core/srcEnv/org/eclipse/statet/rj/renv/core/RPkgUtils.java
@@ -14,6 +14,8 @@
 
 package org.eclipse.statet.rj.renv.core;
 
+import java.util.Locale;
+
 import com.ibm.icu.text.Collator;
 
 import org.eclipse.statet.jcommons.lang.NonNullByDefault;
@@ -46,7 +48,7 @@
 			return RPkgType.SOURCE;
 		}
 		if (isWin(rPlatform)) {
-			if (fileName.toLowerCase().endsWith(".zip")) { //$NON-NLS-1$
+			if (fileName.endsWith(".zip") || fileName.toLowerCase(Locale.ROOT).endsWith(".zip")) { //$NON-NLS-1$ //$NON-NLS-2$
 				return RPkgType.BINARY;
 			}
 		}