diff --git a/HISTORY.rst b/HISTORY.rst
index ceef275e..d2462c79 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -10,6 +10,7 @@ PlatformIO Core 4.0
 ~~~~~~~~~~~~~~~~~~
 
 * Handle project configuration (monitor, test, and upload options) for PIO Remote commands (`issue #2591 <https://github.com/platformio/platformio-core/issues/2591>`_)
+* Warn about about broken library manifest when scanning dependencies (`issue #3268 <https://github.com/platformio/platformio-core/issues/3268>`_)
 * Fixed an issue with the broken latest news for PIO Home
 * Fixed an issue when ``env.BoardConfig()`` does not work for custom boards in extra scripts of libraries (`issue #3264 <https://github.com/platformio/platformio-core/issues/3264>`_)
 
diff --git a/platformio/builder/tools/piolib.py b/platformio/builder/tools/piolib.py
index d5c58ff8..bd4bcf74 100644
--- a/platformio/builder/tools/piolib.py
+++ b/platformio/builder/tools/piolib.py
@@ -33,7 +33,10 @@ from platformio import exception, fs, util
 from platformio.builder.tools import platformio as piotool
 from platformio.compat import WINDOWS, hashlib_encode_data, string_types
 from platformio.managers.lib import LibraryManager
-from platformio.package.manifest.parser import ManifestParserFactory
+from platformio.package.manifest.parser import (
+    ManifestParserError,
+    ManifestParserFactory,
+)
 from platformio.project.options import ProjectOptions
 
 
@@ -108,7 +111,14 @@ class LibBuilderBase(object):
         self.path = realpath(env.subst(path))
         self.verbose = verbose
 
-        self._manifest = manifest if manifest else self.load_manifest()
+        try:
+            self._manifest = manifest if manifest else self.load_manifest()
+        except ManifestParserError:
+            click.secho(
+                "Warning! Ignoring broken library manifest in " + self.path, fg="yellow"
+            )
+            self._manifest = {}
+
         self._is_dependent = False
         self._is_built = False
         self._depbuilders = list()