diff --git a/MANIFEST.in b/MANIFEST.in
index b2e589b..9651ceb 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -6,3 +6,5 @@ include *.md
 recursive-include rattail_corepos/corepos/office/scripts *.php
 
 recursive-include rattail_corepos/db/alembic *.py
+
+recursive-include rattail_corepos/templates *.mako
diff --git a/rattail_corepos/emails.py b/rattail_corepos/emails.py
index ea254df..5d7484a 100644
--- a/rattail_corepos/emails.py
+++ b/rattail_corepos/emails.py
@@ -2,7 +2,7 @@
 ################################################################################
 #
 #  Rattail -- Retail Software Framework
-#  Copyright © 2010-2020 Lance Edgar
+#  Copyright © 2010-2023 Lance Edgar
 #
 #  This file is part of Rattail.
 #
@@ -24,7 +24,7 @@
 Email profiles for Rattail / CORE-POS integration
 """
 
-from rattail.emails import ImporterEmail
+from rattail.emails import ImporterEmail, ProblemReportEmail
 
 
 class core_office_export_lane_op_updates(ImporterEmail):
@@ -35,6 +35,25 @@ class core_office_export_lane_op_updates(ImporterEmail):
     abstract = False
 
 
+class corepos_problems_invalid_person_numbers(ProblemReportEmail):
+    """
+    Looks for `custdata` records with invalid person number sequence.
+    """
+    default_subject = "Invalid person numbers"
+    abstract = False
+
+    def sample_data(self, request):
+        from corepos.db.office_op import model as corepos
+
+        customer = corepos.CustData(card_number=42,
+                                    first_name="Fred",
+                                    last_name="Flintstone",
+                                    person_number=2)
+        return {
+            'problems': [(customer, 1)]
+        }
+
+
 class rattail_import_corepos_api_updates(ImporterEmail):
     """
     Sent when a CORE-POS API -> Rattail import involves data changes.
diff --git a/rattail_corepos/problems/__init__.py b/rattail_corepos/problems/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/rattail_corepos/problems/corepos.py b/rattail_corepos/problems/corepos.py
new file mode 100644
index 0000000..c4590b0
--- /dev/null
+++ b/rattail_corepos/problems/corepos.py
@@ -0,0 +1,58 @@
+# -*- coding: utf-8; -*-
+################################################################################
+#
+#  Rattail -- Retail Software Framework
+#  Copyright © 2010-2023 Lance Edgar
+#
+#  This file is part of Rattail.
+#
+#  Rattail is free software: you can redistribute it and/or modify it under the
+#  terms of the GNU General Public License as published by the Free Software
+#  Foundation, either version 3 of the License, or (at your option) any later
+#  version.
+#
+#  Rattail is distributed in the hope that it will be useful, but WITHOUT ANY
+#  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+#  FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+#  details.
+#
+#  You should have received a copy of the GNU General Public License along with
+#  Rattail.  If not, see <http://www.gnu.org/licenses/>.
+#
+################################################################################
+"""
+Problem reports for CORE-POS
+"""
+
+from corepos.db.office_op import Session as CoreSession, model as corepos
+
+from rattail.problems import ProblemReport
+
+
+class InvalidPersonNumbers(ProblemReport):
+    """
+    Looks for `custdata` records in CORE which have invalid person
+    number sequence.
+    """
+    system_key = 'corepos'
+    problem_key = 'invalid_person_numbers'
+    problem_title = "Invalid person numbers"
+
+    def find_problems(self, **kwargs):
+        problems = []
+        core_session = CoreSession()
+
+        core_members = core_session.query(corepos.MemberInfo)\
+                                   .order_by(corepos.MemberInfo.card_number)\
+                                   .all()
+
+        def inspect(member, i):
+            for j, customer in enumerate(member.customers, 1):
+                if customer.person_number != j:
+                    problems.append((customer, j))
+
+        self.progress_loop(inspect, core_members,
+                           message="Looking for invalid person numbers")
+
+        core_session.close()
+        return problems
diff --git a/rattail_corepos/templates/mail/corepos_problems_invalid_person_numbers.html.mako b/rattail_corepos/templates/mail/corepos_problems_invalid_person_numbers.html.mako
new file mode 100644
index 0000000..0eabfb5
--- /dev/null
+++ b/rattail_corepos/templates/mail/corepos_problems_invalid_person_numbers.html.mako
@@ -0,0 +1,24 @@
+## -*- coding: utf-8; -*-
+<%inherit file="/base_problems.html.mako" />
+
+<%def name="summary()">
+  <p>
+    There are ${len(problems)} customer records which have unexpected
+    person number sequence.&nbsp; This may throw off some logic which
+    expects the sequence to be valid.&nbsp; Please investigate and fix
+    at your convenience.
+  </p>
+</%def>
+
+<%def name="simple_row(obj, i)">
+  <% customer, expected_person_number = obj %>
+  <tr>
+    <td>${customer.card_number}</td>
+    <td>${customer.first_name}</td>
+    <td>${customer.last_name}</td>
+    <td>${expected_person_number}</td>
+    <td>${customer.person_number}</td>
+  </tr>
+</%def>
+
+${self.simple_table(["Card #", "First Name", "Last Name", "Expected Person #", "Current Person #"])}
diff --git a/setup.cfg b/setup.cfg
index 63bf0b8..a82b14a 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -60,6 +60,9 @@ rattail.commands =
         import-corepos-api = rattail_corepos.commands:ImportCOREPOSAPI
         import-corepos-db = rattail_corepos.commands:ImportCOREPOSDB
 
+rattail.emails =
+        rattail_corepos = rattail_corepos.emails
+
 rattail.importing =
         to_rattail.from_corepos_api.import = rattail_corepos.importing.corepos.api:FromCOREPOSToRattail
         to_rattail.from_corepos_db_office_op.import = rattail_corepos.importing.corepos.db:FromCOREPOSToRattail