diff --git a/Lib/idlelib/News3.txt b/Lib/idlelib/News3.txt
index c92196f1f4a642..39791d60c06829 100644
--- a/Lib/idlelib/News3.txt
+++ b/Lib/idlelib/News3.txt
@@ -4,6 +4,9 @@ Released after 2023-10-02
 =========================
 
 
+gh-78889: Stop Shell freezes by blocking user access to non-method
+sys.stdout.shell attributes, which are all private.
+
 gh-78955: Use user-selected color theme for Help => IDLE Doc.
 
 gh-96905: In idlelib code, stop redefining built-ins 'dict' and 'object'.
diff --git a/Lib/idlelib/run.py b/Lib/idlelib/run.py
index 53e80a9b42801f..476a7b26c004b5 100644
--- a/Lib/idlelib/run.py
+++ b/Lib/idlelib/run.py
@@ -436,6 +436,9 @@ class StdioFile(io.TextIOBase):
 
     def __init__(self, shell, tags, encoding='utf-8', errors='strict'):
         self.shell = shell
+        # GH-78889: accessing unpickleable attributes freezes Shell.
+        # IDLE only needs methods; allow 'width' for possible use.
+        self.shell._RPCProxy__attributes = {'width': 1}
         self.tags = tags
         self._encoding = encoding
         self._errors = errors
diff --git a/Misc/NEWS.d/next/IDLE/2024-07-16-16-57-03.gh-issue-78889.U7ghFD.rst b/Misc/NEWS.d/next/IDLE/2024-07-16-16-57-03.gh-issue-78889.U7ghFD.rst
new file mode 100644
index 00000000000000..604194ebb2e859
--- /dev/null
+++ b/Misc/NEWS.d/next/IDLE/2024-07-16-16-57-03.gh-issue-78889.U7ghFD.rst
@@ -0,0 +1,2 @@
+Stop Shell freezes by blocking user access to non-method sys.stdout.shell attributes,
+which are all private.