diff --git a/conf/evolutions/default/136.sql b/conf/evolutions/default/136.sql
new file mode 100644
index 0000000000..6511c06ec0
--- /dev/null
+++ b/conf/evolutions/default/136.sql
@@ -0,0 +1,15 @@
+-- SPDX-FileCopyrightText: 2024 The members of the EXAM Consortium
+--
+-- SPDX-License-Identifier: EUPL-1.2
+
+# --- !Ups
+CREATE EXTENSION IF NOT EXISTS btree_gist;
+ALTER TABLE reservation
+    ADD CONSTRAINT no_double_bookings
+        EXCLUDE USING gist (
+        machine_id WITH =,
+        tstzrange(start_at, end_at) WITH &&
+        );
+
+# --- !Downs
+ALTER TABLE reservation DROP CONSTRAINT no_double_bookings;
diff --git a/scripts/internal/create_assessments.py b/scripts/internal/create_assessments.py
index 56905e8de8..d93db1e936 100644
--- a/scripts/internal/create_assessments.py
+++ b/scripts/internal/create_assessments.py
@@ -11,7 +11,7 @@
 import random
 import string
 
-conn_string = "host='localhost' dbname='sitnet' user='sitnet' password='sitnet'"
+conn_string = "host='localhost' dbname='exam' user='exam' password='exam'"
 conn = connect(conn_string)
 cursor = conn.cursor()
 
diff --git a/scripts/internal/remove_overlapping.py b/scripts/internal/remove_overlapping.py
new file mode 100644
index 0000000000..35c4b16383
--- /dev/null
+++ b/scripts/internal/remove_overlapping.py
@@ -0,0 +1,83 @@
+#!/usr/bin/python
+
+# SPDX-FileCopyrightText: 2024 The members of the EXAM Consortium
+#
+# SPDX-License-Identifier: EUPL-1.2
+
+from datetime import datetime
+from psycopg import connect  # pip install "psycopg[binary]"
+
+conn_string = "host='localhost' dbname='exam' user='exam' password='exam'"
+conn = connect(conn_string)
+cursor = conn.cursor()
+
+
+def select():
+    names = [desc[0] for desc in cursor.description]
+    result = map(dict, [[(names[i], row[i]) for (i, name) in enumerate(names)] for row in cursor])
+    return list(result)
+
+
+def delete(ids):
+    ids = ','.join([str(id) for id in ids])
+    cursor.execute('UPDATE exam_enrolment SET reservation_id = NULL where reservation_id IN (%s)' % ids)
+    cursor.execute('UPDATE exam_participation SET reservation_id = NULL where reservation_id IN (%s)' % ids)
+    cursor.execute('DELETE FROM reservation WHERE id IN (%s)' % ids)
+
+
+def reservations():
+    cursor.execute("""
+        SELECT r.*, ep.id AS ep_id FROM reservation AS r 
+        LEFT JOIN exam_participation AS ep ON ep.reservation_id = r.id WHERE r.machine_id IS NOT NULL
+        """)
+    return select()
+
+
+def find_overlapping(rs):
+    overlapping_pairs = []
+    rs.sort(key=lambda x: (x["machine_id"], x["start_at"]))
+    for i, res1 in enumerate(rs):
+        for j in range(i + 1, len(rs)):
+            res2 = rs[j]
+            # Stop checking if machine_id changes or start time exceeds res1's end time
+            if res1["machine_id"] != res2["machine_id"] or res2["start_at"] > res1["end_at"]:
+                break
+            # Check for overlap
+            if res1["end_at"] > res2["start_at"]:
+                overlapping_pairs.append((res1, res2))
+    return overlapping_pairs
+
+
+def main():
+    rs, removed, unresolved = reservations(), set(), set()
+    print("Following overlapping reservation pairs found:")
+    for r1, r2 in find_overlapping(rs):
+        print(
+            "r1_id: {id1} r2_id:{id2} r1_machine_id: {mid1} r2_machine_id: {mid2} r1_period: {s1} - {e1} r2_period {s2} - {e2}".format(
+                id1=r1['id'], id2=r2['id'], mid1=r1['machine_id'], mid2=r2['machine_id'], s1=r1['start_at'],
+                e1=r1['end_at'], s2=r2['start_at'], e2=r2['end_at']
+            ))
+        if r1['ep_id'] and not r2['ep_id']:
+            print('Reservation #%s will be removed' % r2['id'])
+            removed.add(r2['id'])
+        elif r2['ep_id'] and not r1['ep_id']:
+            print('Reservation #%s will be removed' % r1['id'])
+            removed.add(r1['id'])
+        elif not r1['ep_id'] and not r2['ep_id']:
+            print('Reservation #%s will be removed' % r1['id'])
+            print('Reservation #%s will be removed' % r2['id'])
+            removed.update([r1['id'], r2['id']])
+        else:
+            print('Will not automatically remove reservations #%s and #%s as both are linked to some participation'
+                  % (r1['id'], r2['id']))
+            unresolved.update([r1['id'], r2['id']])
+    print('Conclusion')
+    print('The following reservations will be removed: \n%s' % removed)
+    print('The following reservations must be removed by hand: \n%s' % unresolved)
+    if len(removed) > 0:
+        delete(removed)
+    conn.commit()
+
+
+if __name__ == "__main__":
+    main()