diff --git a/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnersExceptionHook.java b/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnersExceptionHook.java
index c7da676..5eb316c 100644
--- a/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnersExceptionHook.java
+++ b/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnersExceptionHook.java
@@ -52,9 +52,7 @@
 
   @Override
   public boolean skipRetryWithTrace(String actionType, String actionName, Throwable throwable) {
-    return isInvalidPluginConfigurationException(throwable)
-        || isInvalidCodeOwnerConfigException(throwable)
-        || isInvalidPathException(throwable);
+    return isCausedByConfigurationError(throwable);
   }
 
   @Override
@@ -102,9 +100,7 @@
 
   @Override
   public Optional<Status> getStatus(Throwable throwable) {
-    if (isInvalidPluginConfigurationException(throwable)
-        || isInvalidCodeOwnerConfigException(throwable)
-        || isInvalidPathException(throwable)) {
+    if (isCausedByConfigurationError(throwable)) {
       return Optional.of(Status.create(409, "Conflict"));
     }
     return Optional.empty();
@@ -115,6 +111,28 @@
     return getCause(CodeOwnersInternalServerErrorException.class, throwable);
   }
 
+  public static boolean isCausedByConfigurationError(Throwable throwable) {
+    return isInvalidPluginConfigurationException(throwable)
+        || isInvalidCodeOwnerConfigException(throwable)
+        || isInvalidPathException(throwable);
+  }
+
+  public static Optional<? extends Exception> getCauseOfConfigurationError(Throwable throwable) {
+    Optional<InvalidPathException> invalidPathException =
+        CodeOwnersExceptionHook.getInvalidPathException(throwable);
+    if (invalidPathException.isPresent()) {
+      return invalidPathException;
+    }
+
+    Optional<InvalidPluginConfigurationException> invalidPluginConfigurationException =
+        CodeOwnersExceptionHook.getInvalidPluginConfigurationCause(throwable);
+    if (invalidPluginConfigurationException.isPresent()) {
+      return invalidPluginConfigurationException;
+    }
+
+    return CodeOwners.getInvalidCodeOwnerConfigCause(throwable);
+  }
+
   private static boolean isInvalidPluginConfigurationException(Throwable throwable) {
     return getInvalidPluginConfigurationCause(throwable).isPresent();
   }
diff --git a/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnersOnAddReviewer.java b/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnersOnAddReviewer.java
index 4e81f46..ae1f477 100644
--- a/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnersOnAddReviewer.java
+++ b/java/com/google/gerrit/plugins/codeowners/backend/CodeOwnersOnAddReviewer.java
@@ -165,9 +165,17 @@
               })
           .call();
     } catch (Exception e) {
-      logger.atSevere().withCause(e).log(
-          "Failed to post code-owners change message for reviewer on change %s in project %s.",
-          changeId, projectName);
+      Optional<? extends Exception> configurationError =
+          CodeOwnersExceptionHook.getCauseOfConfigurationError(e);
+      if (configurationError.isPresent()) {
+        logger.atWarning().log(
+            "Failed to post code-owners change message for reviewer on change %s in project %s: %s",
+            changeId, projectName, configurationError.get().getMessage());
+      } else {
+        logger.atSevere().withCause(e).log(
+            "Failed to post code-owners change message for reviewer on change %s in project %s.",
+            changeId, projectName);
+      }
     }
   }
 
diff --git a/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerApproval.java b/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerApproval.java
index b538ebd..907f065 100644
--- a/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerApproval.java
+++ b/java/com/google/gerrit/plugins/codeowners/backend/OnCodeOwnerApproval.java
@@ -17,6 +17,7 @@
 import static com.google.common.base.Preconditions.checkState;
 
 import com.google.common.collect.ImmutableList;
+import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.entities.PatchSet;
 import com.google.gerrit.metrics.Timer0;
 import com.google.gerrit.plugins.codeowners.backend.config.CodeOwnersPluginConfiguration;
@@ -51,6 +52,8 @@
  */
 @Singleton
 class OnCodeOwnerApproval implements OnPostReview {
+  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
+
   private final CodeOwnersPluginConfiguration codeOwnersPluginConfiguration;
   private final CodeOwnerApprovalCheck codeOwnerApprovalCheck;
   private final CodeOwnerMetrics codeOwnerMetrics;
@@ -103,6 +106,23 @@
           approvals,
           requiredApproval,
           maxPathsInChangeMessage);
+    } catch (Exception e) {
+      Optional<? extends Exception> configurationError =
+          CodeOwnersExceptionHook.getCauseOfConfigurationError(e);
+      if (configurationError.isPresent()) {
+        logger.atWarning().log(
+            "Failed to post code-owners change message for code owner approval on change %s"
+                + " in project %s: %s",
+            changeNotes.getChangeId(),
+            changeNotes.getProjectName(),
+            configurationError.get().getMessage());
+      } else {
+        logger.atSevere().withCause(e).log(
+            "Failed to post code-owners change message for code owner approval on change %s"
+                + " in project %s.",
+            changeNotes.getChangeId(), changeNotes.getProjectName());
+      }
+      return Optional.empty();
     }
   }
 
diff --git a/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/CodeOwnersOnAddReviewerIT.java b/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/CodeOwnersOnAddReviewerIT.java
index bfc0283..70fb164 100644
--- a/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/CodeOwnersOnAddReviewerIT.java
+++ b/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/CodeOwnersOnAddReviewerIT.java
@@ -83,6 +83,18 @@
   }
 
   @Test
+  public void noChangeMessageAddedIfInvalidCodeOwnerConfigFilesExist() throws Exception {
+    createNonParseableCodeOwnerConfig(getCodeOwnerConfigFileName());
+
+    String changeId = createChange("Test Change", "foo/bar.baz", "file content").getChangeId();
+
+    gApi.changes().id(changeId).addReviewer(user.email());
+
+    Collection<ChangeMessageInfo> messages = gApi.changes().id(changeId).get().messages;
+    assertThat(Iterables.getLast(messages).message).isEqualTo("Uploaded patch set 1.");
+  }
+
+  @Test
   public void changeMessageListsOwnedPaths() throws Exception {
     codeOwnerConfigOperations
         .newCodeOwnerConfig()
diff --git a/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/OnCodeOwnerApprovalIT.java b/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/OnCodeOwnerApprovalIT.java
index efd2166..d3fe19a 100644
--- a/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/OnCodeOwnerApprovalIT.java
+++ b/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/OnCodeOwnerApprovalIT.java
@@ -65,6 +65,19 @@
   }
 
   @Test
+  public void changeMessageNotExtendedIfInvalidCodeOwnerConfigFilesExist() throws Exception {
+    createNonParseableCodeOwnerConfig(getCodeOwnerConfigFileName());
+
+    String path = "foo/bar.baz";
+    String changeId = createChange("Test Change", path, "file content").getChangeId();
+
+    recommend(changeId);
+
+    Collection<ChangeMessageInfo> messages = gApi.changes().id(changeId).get().messages;
+    assertThat(Iterables.getLast(messages).message).isEqualTo("Patch Set 1: Code-Review+1");
+  }
+
+  @Test
   public void changeMessageListsNewlyApprovedPaths() throws Exception {
     codeOwnerConfigOperations
         .newCodeOwnerConfig()