diff --git a/pyproject.toml b/pyproject.toml
index 40189e1..36ad68d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -23,6 +23,8 @@ classifiers = [
 ]
 dependencies = [
     "setuptools",
+    # py2app 0.28.10 calls spawn(cmd, verbose=...), which setuptools 84 passes on to subprocess.
+    "setuptools<84; sys_platform == 'darwin'",
     "innosetup_builder @ git+https://github.com/accessibleapps/innosetup_builder.git",
     "py2exe; sys_platform == 'win32'",
     "pywin32; sys_platform == 'win32'",