diff --git a/locales/en.json b/locales/en.json
index 7275a3b6f..e44f87778 100644
--- a/locales/en.json
+++ b/locales/en.json
@@ -209,6 +209,8 @@
     "service_unknown": "Unknown service '{service:s}'",
     "ssowat_conf_generated": "The SSOwat configuration has been generated",
     "ssowat_conf_updated": "The SSOwat configuration has been updated",
+    "ssowat_persistent_conf_read_error": "Error while reading SSOwat persistent configuration: {error:s}. Edit /etc/ssowat/conf.json.persistent file to fix the JSON syntax.",
+    "ssowat_persistent_conf_write_error": "Error while saving SSOwat persistent configuration: {error:s}. Edit /etc/ssowat/conf.json.persistent file to fix the JSON syntax.",
     "system_upgraded": "The system has been upgraded",
     "system_username_exists": "Username already exists in the system users",
     "unbackup_app": "App '{app:s}' will not be saved",
diff --git a/src/yunohost/app.py b/src/yunohost/app.py
index a30690018..0da66608b 100644
--- a/src/yunohost/app.py
+++ b/src/yunohost/app.py
@@ -809,6 +809,9 @@ def app_makedefault(auth, app, domain=None):
     try:
         with open('/etc/ssowat/conf.json.persistent') as json_conf:
             ssowat_conf = json.loads(str(json_conf.read()))
+    except ValueError as e:
+        raise MoulinetteError(errno.EINVAL,
+                              m18n.n('ssowat_persistent_conf_read_error', error=e.strerror))
     except IOError:
         ssowat_conf = {}
 
@@ -817,8 +820,13 @@ def app_makedefault(auth, app, domain=None):
 
     ssowat_conf['redirected_urls'][domain +'/'] = app_domain + app_path
 
-    with open('/etc/ssowat/conf.json.persistent', 'w+') as f:
-        json.dump(ssowat_conf, f, sort_keys=True, indent=4)
+    try:
+        with open('/etc/ssowat/conf.json.persistent', 'w+') as f:
+            json.dump(ssowat_conf, f, sort_keys=True, indent=4)
+    except IOError as e:
+        raise MoulinetteError(errno.EPERM,
+                              m18n.n('ssowat_persistent_conf_write_error', error=e.strerror))
+
 
     os.system('chmod 644 /etc/ssowat/conf.json.persistent')
 
diff --git a/src/yunohost/tools.py b/src/yunohost/tools.py
index ce0ced1ab..475bf9b7f 100644
--- a/src/yunohost/tools.py
+++ b/src/yunohost/tools.py
@@ -244,6 +244,9 @@ def tools_postinstall(domain, password, ignore_dyndns=False):
     try:
         with open('/etc/ssowat/conf.json.persistent') as json_conf:
             ssowat_conf = json.loads(str(json_conf.read()))
+    except ValueError as e:
+        raise MoulinetteError(errno.EINVAL,
+                              m18n.n('ssowat_persistent_conf_read_error', error=e.strerror))
     except IOError:
         ssowat_conf = {}
 
@@ -252,8 +255,13 @@ def tools_postinstall(domain, password, ignore_dyndns=False):
 
     ssowat_conf['redirected_urls']['/'] = domain +'/yunohost/admin'
 
-    with open('/etc/ssowat/conf.json.persistent', 'w+') as f:
-        json.dump(ssowat_conf, f, sort_keys=True, indent=4)
+    try:
+        with open('/etc/ssowat/conf.json.persistent', 'w+') as f:
+            json.dump(ssowat_conf, f, sort_keys=True, indent=4)
+    except IOError as e:
+        raise MoulinetteError(errno.EPERM,
+                              m18n.n('ssowat_persistent_conf_write_error', error=e.strerror))
+
 
     os.system('chmod 644 /etc/ssowat/conf.json.persistent')
 
diff --git a/src/yunohost/user.py b/src/yunohost/user.py
index f5ac25ea8..f1b47f799 100644
--- a/src/yunohost/user.py
+++ b/src/yunohost/user.py
@@ -176,14 +176,20 @@ def user_create(auth, username, firstname, lastname, mail, password,
         try:
             with open('/etc/ssowat/conf.json.persistent') as json_conf:
                 ssowat_conf = json.loads(str(json_conf.read()))
+        except ValueError as e:
+            raise MoulinetteError(errno.EINVAL,
+                                  m18n.n('ssowat_persistent_conf_read_error', error=e.strerror))
+        except IOError:
+            ssowat_conf = {}
 
-            if 'redirected_urls' in ssowat_conf and '/' in ssowat_conf['redirected_urls']:
-                del ssowat_conf['redirected_urls']['/']
-
-            with open('/etc/ssowat/conf.json.persistent', 'w+') as f:
-                json.dump(ssowat_conf, f, sort_keys=True, indent=4)
-
-        except IOError: pass
+        if 'redirected_urls' in ssowat_conf and '/' in ssowat_conf['redirected_urls']:
+            del ssowat_conf['redirected_urls']['/']
+            try:
+                with open('/etc/ssowat/conf.json.persistent', 'w+') as f:
+                    json.dump(ssowat_conf, f, sort_keys=True, indent=4)
+            except IOError as e:
+                raise MoulinetteError(errno.EPERM,
+                                      m18n.n('ssowat_persistent_conf_write_error', error=e.strerror))
 
 
     if auth.add(rdn, attr_dict):