diff --git a/tinylog-api/src/main/java/org/tinylog/runtime/LegacyJavaRuntime.java b/tinylog-api/src/main/java/org/tinylog/runtime/LegacyJavaRuntime.java
index 3f80253a..aa731ba6 100644
--- a/tinylog-api/src/main/java/org/tinylog/runtime/LegacyJavaRuntime.java
+++ b/tinylog-api/src/main/java/org/tinylog/runtime/LegacyJavaRuntime.java
@@ -27,7 +27,7 @@
  */
 public final class LegacyJavaRuntime extends AbstractJavaRuntime {
 
-	private static final Timestamp startTime = new LegacyTimestamp(ManagementFactory.getRuntimeMXBean().getStartTime());
+	private static final Timestamp startTime = new LegacyTimestamp(System.currentTimeMillis());
 
 	private final boolean hasSunReflection;
 	private final Method stackTraceElementGetter;
diff --git a/tinylog-api/src/main/java/org/tinylog/runtime/ModernJavaRuntime.java b/tinylog-api/src/main/java/org/tinylog/runtime/ModernJavaRuntime.java
index 524981ea..40b54b3b 100644
--- a/tinylog-api/src/main/java/org/tinylog/runtime/ModernJavaRuntime.java
+++ b/tinylog-api/src/main/java/org/tinylog/runtime/ModernJavaRuntime.java
@@ -14,7 +14,6 @@
 package org.tinylog.runtime;
 
 import java.lang.StackWalker.StackFrame;
-import java.lang.management.ManagementFactory;
 import java.util.Iterator;
 import java.util.Locale;
 import java.util.function.Function;
@@ -31,8 +30,8 @@
 final class ModernJavaRuntime extends AbstractJavaRuntime {
 
 	private static final Timestamp startTime = new PreciseTimestamp(
-		ManagementFactory.getRuntimeMXBean().getStartTime(),
-		0
+			System.currentTimeMillis(),
+			0
 	);
 
 	private final ProcessHandle currentProcess = getCurrentProcess();