diff --git a/src/calibre/utils/filenames.py b/src/calibre/utils/filenames.py
index bf3cbe2f67..82d3487c5f 100644
--- a/src/calibre/utils/filenames.py
+++ b/src/calibre/utils/filenames.py
@@ -63,6 +63,8 @@ def shorten_components_to(length, components):
             if not r:
                 r = x.strip()[0] if x.strip() else 'x'
         ans.append(r)
+    if len(os.sep.join(ans)) > length:
+        return shorten_components_to(length, ans)
     return ans
 
 def find_executable_in_path(name, path=None):