diff --git a/src/calibre/ebooks/oeb/transforms/metadata.py b/src/calibre/ebooks/oeb/transforms/metadata.py
index b1141f72b4..dbbdeb3c52 100644
--- a/src/calibre/ebooks/oeb/transforms/metadata.py
+++ b/src/calibre/ebooks/oeb/transforms/metadata.py
@@ -171,11 +171,14 @@ class MergeMetadata(object):
         for item in self.oeb.spine:
             try:
                 images = XPath('//h:img[@src]')(item.data)
-            except:
-                images = []
+            except Exception:
+                images = ()
             removed = False
             for img in images:
-                href = item.abshref(img.get('src'))
+                try:
+                    href = item.abshref(img.get('src'))
+                except Exception:
+                    continue  # Invalid URL, ignore
                 if href == cover_item.href:
                     img.getparent().remove(img)
                     removed = True
@@ -195,6 +198,3 @@ class MergeMetadata(object):
                         ' the cover image'%item.href)
                 self.oeb.spine.remove(item)
                 self.oeb.manifest.remove(item)
-
-
-