diff --git a/CHANGELOG.adoc b/CHANGELOG.adoc
index 2c3bfa2ff..4593f0498 100644
--- a/CHANGELOG.adoc
+++ b/CHANGELOG.adoc
@@ -8,6 +8,7 @@ Release with new features and bugfixes:
 
 * https://github.com/devonfw/IDEasy/issues/1552[#1552]: Add Commandlet to fix TLS issue
 * https://github.com/devonfw/IDEasy/issues/1799[#1799]: Add support for file URL in GitUrl validation for local development
+* https://github.com/devonfw/IDEasy/issues/451[#451]: Automatically remove macOS quarantine attribute after tool extraction
 * https://github.com/devonfw/IDEasy/issues/1760[#1760]: Accept empty input for single option
 
 The full list of changes for this release can be found in https://github.com/devonfw/IDEasy/milestone/43?closed=1[milestone 2026.04.002].
diff --git a/cli/src/main/java/com/devonfw/tools/ide/os/MacOsHelper.java b/cli/src/main/java/com/devonfw/tools/ide/os/MacOsHelper.java
index 1d631427d..7bfec4615 100644
--- a/cli/src/main/java/com/devonfw/tools/ide/os/MacOsHelper.java
+++ b/cli/src/main/java/com/devonfw/tools/ide/os/MacOsHelper.java
@@ -12,6 +12,8 @@
 
 import com.devonfw.tools.ide.context.IdeContext;
 import com.devonfw.tools.ide.io.FileAccess;
+import com.devonfw.tools.ide.process.ProcessMode;
+import com.devonfw.tools.ide.process.ProcessResult;
 import com.devonfw.tools.ide.tool.ToolCommandlet;
 import com.devonfw.tools.ide.tool.repository.ToolRepository;
 
@@ -25,6 +27,8 @@ public final class MacOsHelper {
   private static final Set<String> INVALID_LINK_FOLDERS = Set.of(IdeContext.FOLDER_CONTENTS,
       IdeContext.FOLDER_RESOURCES, IdeContext.FOLDER_BIN);
 
+  private final IdeContext context;
+
   private final FileAccess fileAccess;
 
   private final SystemInfo systemInfo;
@@ -36,7 +40,10 @@ public final class MacOsHelper {
    */
   public MacOsHelper(IdeContext context) {
 
-    this(context.getFileAccess(), context.getSystemInfo());
+    super();
+    this.context = context;
+    this.fileAccess = context.getFileAccess();
+    this.systemInfo = context.getSystemInfo();
   }
 
   /**
@@ -48,10 +55,54 @@ public MacOsHelper(IdeContext context) {
   public MacOsHelper(FileAccess fileAccess, SystemInfo systemInfo) {
 
     super();
+    this.context = null;
     this.fileAccess = fileAccess;
     this.systemInfo = systemInfo;
   }
 
+  /**
+   * Fixes macOS Gatekeeper blocking for downloaded tools. On macOS 15.1+ (Apple Silicon), just removing {@code com.apple.quarantine} is not enough since
+   * unsigned apps still get the "is damaged" error. So we clear all xattrs first, then ad-hoc codesign any {@code .app} bundles. Call this after writing
+   * {@code .ide.software.version} since codesigning seals the bundle.
+   *
+   * @param path the {@link Path} to the installation directory.
+   */
+  public void removeQuarantineAttribute(Path path) {
+
+    if (!this.systemInfo.isMac()) {
+      return;
+    }
+    if (this.context == null) {
+      LOG.debug("Cannot fix Gatekeeper for {} - no context available", path);
+      return;
+    }
+    // clear all extended attributes (quarantine, resource forks, etc.)
+    LOG.debug("Clearing extended attributes from {}", path);
+    try {
+      this.context.newProcess().executable("xattr").addArgs("-cr", path).run(ProcessMode.DEFAULT_SILENT);
+    } catch (Exception e) {
+      LOG.warn("Could not clear extended attributes from {}: {}", path, e.getMessage(), e);
+    }
+    // ad-hoc codesign .app bundles only if they are not already properly signed (e.g. Eclipse is notarized - we must not replace that)
+    Path appDir = findAppDir(path);
+    if (appDir != null) {
+      try {
+        ProcessResult verifyResult = this.context.newProcess().executable("codesign")
+            .addArgs("-v", appDir).run(ProcessMode.DEFAULT_SILENT);
+        if (!verifyResult.isSuccessful()) {
+          LOG.debug("Ad-hoc codesigning {}", appDir);
+          ProcessResult signResult = this.context.newProcess().executable("codesign")
+              .addArgs("--force", "--deep", "--sign", "-", appDir).run(ProcessMode.DEFAULT_SILENT);
+          if (!signResult.isSuccessful()) {
+            LOG.warn("Could not codesign {} - app may be blocked by Gatekeeper", appDir);
+          }
+        }
+      } catch (Exception e) {
+        LOG.warn("Codesign not available for {}: {}", appDir, e.getMessage(), e);
+      }
+    }
+  }
+
   /**
    * @param rootDir the {@link Path} to the root directory.
    * @return the path to the app directory.
@@ -61,6 +112,41 @@ public Path findAppDir(Path rootDir) {
         p -> p.getFileName().toString().endsWith(".app") && Files.isDirectory(p), false);
   }
 
+  /**
+   * Finds the directory containing the tool's executables inside a macOS {@code .app} bundle, without requiring the binary name. This method exists separately
+   * from {@link #findLinkDir(Path, String)} because it is called from {@code getToolBinPath()}, which is itself called by {@code getBinaryName()} — using
+   * {@code findLinkDir} there would cause infinite recursion since it requires the binary name.
+   *
+   * @param rootDir the {@link Path} to the root directory that may contain a {@code .app} bundle.
+   * @return the binary directory inside the {@code .app} bundle, or {@code rootDir} if not a {@code .app} structure.
+   */
+  public Path findBinDir(Path rootDir) {
+
+    if (!this.systemInfo.isMac() || Files.isDirectory(rootDir.resolve(IdeContext.FOLDER_BIN))) {
+      return rootDir;
+    }
+    Path contentsDir = rootDir.resolve(IdeContext.FOLDER_CONTENTS);
+    if (!Files.isDirectory(contentsDir)) {
+      Path appDir = findAppDir(rootDir);
+      if (appDir == null) {
+        return rootDir;
+      }
+      contentsDir = appDir.resolve(IdeContext.FOLDER_CONTENTS);
+      if (!Files.isDirectory(contentsDir)) {
+        return rootDir;
+      }
+    }
+    Path resourcesApp = contentsDir.resolve(IdeContext.FOLDER_RESOURCES).resolve(IdeContext.FOLDER_APP);
+    if (Files.isDirectory(resourcesApp)) {
+      return resourcesApp;
+    }
+    Path macosDir = contentsDir.resolve("MacOS");
+    if (Files.isDirectory(macosDir)) {
+      return macosDir;
+    }
+    return rootDir;
+  }
+
   /**
    * @param rootDir the {@link Path} to the root directory.
    * @param tool the name of the tool to find the link directory for.
diff --git a/cli/src/main/java/com/devonfw/tools/ide/tool/LocalToolCommandlet.java b/cli/src/main/java/com/devonfw/tools/ide/tool/LocalToolCommandlet.java
index aa7ff9186..8f944dd30 100644
--- a/cli/src/main/java/com/devonfw/tools/ide/tool/LocalToolCommandlet.java
+++ b/cli/src/main/java/com/devonfw/tools/ide/tool/LocalToolCommandlet.java
@@ -65,6 +65,14 @@ public Path getToolBinPath() {
     if (Files.isDirectory(binPath)) {
       return binPath;
     }
+    // on macOS, toolPath may contain a .app bundle - resolve the actual binary dir (e.g. Contents/MacOS/)
+    if (Files.isDirectory(toolPath)) {
+      Path realPath = this.context.getFileAccess().toRealPath(toolPath);
+      Path macBinDir = this.context.getFileAccess().getBinPath(getMacOsHelper().findBinDir(realPath));
+      if (!macBinDir.equals(realPath)) {
+        return macBinDir;
+      }
+    }
     return toolPath;
   }
 
@@ -260,6 +268,8 @@ protected void performToolInstallation(ToolInstallRequest request, Path installa
     fileAccess.mkdirs(installationPath.getParent());
     fileAccess.extract(downloadedToolFile, installationPath, this::postExtract, extract);
     this.context.writeVersionFile(resolvedVersion, installationPath);
+    // fix macOS Gatekeeper blocking - must run after version file is written but before any executables are launched
+    getMacOsHelper().removeQuarantineAttribute(installationPath);
     LOG.debug("Installed {} in version {} at {}", this.tool, resolvedVersion, installationPath);
   }
 
diff --git a/cli/src/main/java/com/devonfw/tools/ide/tool/ToolCommandlet.java b/cli/src/main/java/com/devonfw/tools/ide/tool/ToolCommandlet.java
index 60a1668fe..575f9ed68 100644
--- a/cli/src/main/java/com/devonfw/tools/ide/tool/ToolCommandlet.java
+++ b/cli/src/main/java/com/devonfw/tools/ide/tool/ToolCommandlet.java
@@ -20,7 +20,6 @@
 import com.devonfw.tools.ide.context.IdeContext;
 import com.devonfw.tools.ide.environment.EnvironmentVariables;
 import com.devonfw.tools.ide.environment.EnvironmentVariablesFiles;
-import com.devonfw.tools.ide.io.FileCopyMode;
 import com.devonfw.tools.ide.log.IdeLogLevel;
 import com.devonfw.tools.ide.nls.NlsBundle;
 import com.devonfw.tools.ide.os.MacOsHelper;
@@ -500,8 +499,7 @@ protected ToolInstallation createToolInstallation(Path rootDir, VersionIdentifie
     Path binDir = rootDir;
     if (rootDir != null) {
       // on MacOS applications have a very strange structure - see JavaDoc of findLinkDir and ToolInstallation.linkDir for details.
-      linkDir = getMacOsHelper().findLinkDir(rootDir, getBinaryName());
-      binDir = this.context.getFileAccess().getBinPath(linkDir);
+      binDir = this.context.getFileAccess().getBinPath(getMacOsHelper().findLinkDir(rootDir, getBinaryName()));
     }
     return createToolInstallation(rootDir, linkDir, binDir, version, newInstallation, environmentContext, additionalInstallation);
   }
@@ -520,13 +518,6 @@ protected ToolInstallation createToolInstallation(Path rootDir, VersionIdentifie
   protected ToolInstallation createToolInstallation(Path rootDir, Path linkDir, Path binDir, VersionIdentifier version, boolean newInstallation,
       EnvironmentContext environmentContext, boolean additionalInstallation) {
 
-    if (linkDir != rootDir) {
-      assert (!linkDir.equals(rootDir));
-      Path toolVersionFile = rootDir.resolve(IdeContext.FILE_SOFTWARE_VERSION);
-      if (Files.exists(toolVersionFile)) {
-        this.context.getFileAccess().copy(toolVersionFile, linkDir, FileCopyMode.COPY_FILE_OVERRIDE);
-      }
-    }
     ToolInstallation toolInstallation = new ToolInstallation(rootDir, linkDir, binDir, version, newInstallation);
     setEnvironment(environmentContext, toolInstallation, additionalInstallation);
     return toolInstallation;
diff --git a/cli/src/test/java/com/devonfw/tools/ide/tool/eclipse/EclipseTest.java b/cli/src/test/java/com/devonfw/tools/ide/tool/eclipse/EclipseTest.java
index 3e8dae7ff..bca2ebdfe 100644
--- a/cli/src/test/java/com/devonfw/tools/ide/tool/eclipse/EclipseTest.java
+++ b/cli/src/test/java/com/devonfw/tools/ide/tool/eclipse/EclipseTest.java
@@ -49,7 +49,7 @@ void testEclipse(String os) throws IOException {
         new IdeLogEntry(IdeLogLevel.SUCCESS, "Successfully installed eclipse in version 2024-09", true));
     assertThat(context).logAtSuccess().hasMessage("Successfully ended step 'Install plugin anyedit'.");
     assertThat(context.getPluginsPath().resolve("eclipse")).isDirectory();
-    assertThat(eclipsePath.resolve("eclipsetest")).hasContent(
+    assertThat(eclipse.getToolBinPath().resolve("eclipsetest")).hasContent(
         "eclipse " + os + " -data " + context.getWorkspacePath() + " -keyring " + context.getUserHome().resolve(".eclipse").resolve(".keyring")
             + " -configuration " + context.getPluginsPath().resolve("eclipse").resolve("configuration") + " gui -showlocation eclipseproject");
 
diff --git a/cli/src/test/java/com/devonfw/tools/ide/tool/jmc/JmcTest.java b/cli/src/test/java/com/devonfw/tools/ide/tool/jmc/JmcTest.java
index c54307edf..1fa53fad6 100644
--- a/cli/src/test/java/com/devonfw/tools/ide/tool/jmc/JmcTest.java
+++ b/cli/src/test/java/com/devonfw/tools/ide/tool/jmc/JmcTest.java
@@ -76,7 +76,8 @@ private void checkInstallation(IdeTestContext context) {
       assertThat(context.getSoftwarePath().resolve("jmc/HelloWorld.txt")).hasContent("Hello World!");
       assertThat(context.getSoftwarePath().resolve("jmc/JDK Mission Control")).doesNotExist();
     } else if (context.getSystemInfo().isMac()) {
-      assertThat(context.getSoftwarePath().resolve("jmc/jmc")).exists();
+      Jmc jmc = context.getCommandletManager().getCommandlet(Jmc.class);
+      assertThat(jmc.getToolBinPath().resolve("jmc")).exists();
     }
     assertThat(context.getSoftwarePath().resolve("jmc/.ide.software.version")).exists().hasContent("8.3.0");
     assertThat(context).logAtSuccess().hasMessageContaining("Successfully installed jmc in version 8.3.0");