diff --git a/CHANGELOG.md b/CHANGELOG.md
index 44b068f2..3723e314 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ In Development
 * Fix broken install on OVH VPS's.
 * After installing an SSL certificate from the control panel, the page wasn't being refreshed.
 * The minimum greylisting delay has been reduced from 5 minutes to 3 minutes.
+* Backups broke if the box's hostname was changed after installation.
 
 v0.09 (May 8, 2015)
 -------------------
diff --git a/management/backup.py b/management/backup.py
index c69690ee..40d70458 100755
--- a/management/backup.py
+++ b/management/backup.py
@@ -180,8 +180,9 @@ def perform_backup(full_backup):
 	if len(passphrase) < 43: raise Exception("secret_key.txt's first line is too short!")
 	env_with_passphrase = { "PASSPHRASE" : passphrase }
 
-	# Update the backup mirror directory which mirrors the current
-	# STORAGE_ROOT (but excluding the backups themselves!).
+	# Run a backup of STORAGE_ROOT (but excluding the backups themselves!).
+	# --allow-source-mismatch is needed in case the box's hostname is changed
+	# after the first backup. See #396.
 	try:
 		shell('check_call', [
 			"/usr/bin/duplicity",
@@ -191,7 +192,8 @@ def perform_backup(full_backup):
 			"--volsize", "250",
 			"--gpg-options", "--cipher-algo=AES256",
 			env["STORAGE_ROOT"],
-			"file://" + backup_dir
+			"file://" + backup_dir,
+                        "--allow-source-mismatch"
 			],
 			env_with_passphrase)
 	finally: