diff --git a/erpnext/startup/boot.py b/erpnext/startup/boot.py
index a451995531c..64349479a08 100644
--- a/erpnext/startup/boot.py
+++ b/erpnext/startup/boot.py
@@ -54,6 +54,7 @@ def boot_session(bootinfo):
 				"country",
 				"exchange_gain_loss_account",
 			],
+			limit_page_length=0,  # intentionally unbounded: all companies are needed for boot
 		)
 		for company in companies:
 			company.doctype = ":Company"
diff --git a/erpnext/startup/test_boot.py b/erpnext/startup/test_boot.py
new file mode 100644
index 00000000000..05e3fa7ee6a
--- /dev/null
+++ b/erpnext/startup/test_boot.py
@@ -0,0 +1,22 @@
+# Copyright (c) 2025, Frappe Technologies Pvt. Ltd. and Contributors
+# License: GNU General Public License v3. See license.txt
+
+import frappe
+
+from erpnext.tests.utils import ERPNextTestSuite
+
+
+class TestBoot(ERPNextTestSuite):
+	def test_boot_session_populates_companies_and_party_types(self):
+		# boot_session reads Customer count, Company list and Party Type account types via ORM/qb
+		# (formerly raw SQL with ifnull, which is invalid on Postgres). Exercises that on both engines.
+		from erpnext.startup.boot import boot_session
+
+		bootinfo = frappe._dict(sysdefaults=frappe._dict(), page_info=frappe._dict(), docs=[])
+		boot_session(bootinfo)
+
+		self.assertIsInstance(bootinfo.customer_count, int)
+		self.assertIn("party_account_types", bootinfo)
+
+		company_docs = [d for d in bootinfo.docs if d.get("doctype") == ":Company"]
+		self.assertTrue(any(d.get("name") == "_Test Company" for d in company_docs))