diff --git a/background/style-manager.js b/background/style-manager.js
index 1560f13e..02d051e2 100644
--- a/background/style-manager.js
+++ b/background/style-manager.js
@@ -358,7 +358,7 @@ const styleManager = (() => {
       if (match === 'excluded') {
         excluded = true;
       }
-      for (const section of data.sections) {
+      for (const section of (data.sections || [])) {
         if (styleCodeEmpty(section.code)) {
           continue;
         }
diff --git a/edit/edit.js b/edit/edit.js
index 78b6e78c..0c0d6d3e 100644
--- a/edit/edit.js
+++ b/edit/edit.js
@@ -170,7 +170,6 @@ preinit();
         $('#name').title = usercss ? t('usercssReplaceTemplateName') : '';
 
         $('#preview-label').classList.toggle('hidden', !style.id);
-
         $('#beautify').onclick = () => beautify(editor.getEditors());
         $('#lint').addEventListener('scroll', hideLintHeaderOnScroll, {passive: true});
         window.addEventListener('resize', () => debounce(rememberWindowSize, 100));
@@ -341,19 +340,20 @@ function initStyleData() {
   // TODO: remove .replace(/^\?/, '') when minimum_chrome_version >= 52 (https://crbug.com/601425)
   const params = new URLSearchParams(location.search.replace(/^\?/, ''));
   const id = Number(params.get('id'));
+  const createNewSection = () => [
+    Object.assign({code: ''},
+      ...Object.keys(CssToProperty)
+        .map(name => ({
+          [CssToProperty[name]]: params.get(name) && [params.get(name)] || []
+        }))
+    )
+  ];
   const createEmptyStyle = () => ({
     name: params.get('domain') ||
           tryCatch(() => new URL(params.get('url-prefix')).hostname) ||
           '',
     enabled: true,
-    sections: [
-      Object.assign({code: ''},
-        ...Object.keys(CssToProperty)
-          .map(name => ({
-            [CssToProperty[name]]: params.get(name) && [params.get(name)] || []
-          }))
-      )
-    ],
+    sections: createNewSection(),
   });
   return fetchStyle()
     .then(style => {
@@ -372,7 +372,12 @@ function initStyleData() {
 
   function fetchStyle() {
     if (id) {
-      return API.getStyle(id);
+      return API.getStyle(id).then(style => {
+        if (!style.sections || !style.sections.length) {
+          style.sections = createNewSection();
+        }
+        return style;
+      });
     }
     return Promise.resolve(createEmptyStyle());
   }
diff --git a/edit/sections-editor.js b/edit/sections-editor.js
index 99772f2b..ac72c63e 100644
--- a/edit/sections-editor.js
+++ b/edit/sections-editor.js
@@ -46,7 +46,7 @@ function createSectionsEditor({style, onTitleChanged}) {
 
   let sectionOrder = '';
   const initializing = new Promise(resolve => initSection({
-    sections: style.sections.slice(),
+    sections: (style.sections || []).slice(),
     done:() => {
       // FIXME: implement this with CSS?
       // https://github.com/openstyles/stylus/commit/2895ce11e271788df0e4f7314b3b981fde086574
@@ -436,7 +436,7 @@ function createSectionsEditor({style, onTitleChanged}) {
     function chunk() {
       if (!originalSections.length) {
         setGlobalProgress();
-        if (focusOn !== false) {
+        if (focusOn !== false && sections[focusOn]) {
           setTimeout(() => sections[focusOn].cm.focus());
         }
         container.classList.remove('hidden');
@@ -545,7 +545,7 @@ function createSectionsEditor({style, onTitleChanged}) {
     updateSectionOrder();
   }
 
-  function replaceSections(originalSections) {
+  function replaceSections(originalSections = []) {
     for (const section of sections) {
       section.remove(true);
     }
diff --git a/edit/source-editor.js b/edit/source-editor.js
index 7119cfa5..310c319b 100644
--- a/edit/source-editor.js
+++ b/edit/source-editor.js
@@ -18,7 +18,7 @@ function createSourceEditor({style, onTitleChanged}) {
   const dirty = dirtyReporter();
 
   // normalize style
-  if (!style.id) setupNewStyle(style);
+  if (!style.id || !style.sections.length) setupNewStyle(style);
 
   const cm = cmFactory.create($('.single-editor'), {
     value: style.sourceCode,
@@ -123,6 +123,7 @@ function createSourceEditor({style, onTitleChanged}) {
   }
 
   function setupNewStyle(style) {
+    if (!style.sections) style.sections = [];
     style.sections[0].code = ' '.repeat(prefs.get('editor.tabSize')) +
       `/* ${t('usercssReplaceTemplateSectionBody')} */`;
     let section = sectionsToMozFormat(style);
diff --git a/edit/util.js b/edit/util.js
index cc18b515..7a522b2a 100644
--- a/edit/util.js
+++ b/edit/util.js
@@ -103,7 +103,7 @@ function sectionsToMozFormat(style) {
     domains:     'domain',
     regexps:     'regexp',
   };
-  return style.sections.map(section => {
+  return (style.sections || []).map(section => {
     let cssMds = [];
     for (const i in propertyToCss) {
       if (section[i]) {
diff --git a/install-usercss/install-usercss.js b/install-usercss/install-usercss.js
index afbd6419..53da010d 100644
--- a/install-usercss/install-usercss.js
+++ b/install-usercss/install-usercss.js
@@ -365,7 +365,7 @@
 
   function getAppliesTo(style) {
     function *_gen() {
-      for (const section of style.sections) {
+      for (const section of (style.sections || [])) {
         for (const type of ['urls', 'urlPrefixes', 'domains', 'regexps']) {
           if (section[type]) {
             yield *section[type];
diff --git a/js/messaging.js b/js/messaging.js
index 1ab433b5..8d4ac72b 100644
--- a/js/messaging.js
+++ b/js/messaging.js
@@ -290,8 +290,12 @@ function ignoreChromeError() {
 
 function getStyleWithNoCode(style) {
   const stripped = deepCopy(style);
-  for (const section of stripped.sections) section.code = null;
-  stripped.sourceCode = null;
+  if (stripped.sections && stripped.sections.length) {
+    for (const section of stripped.sections) section.code = null;
+    stripped.sourceCode = null;
+  } else {
+    stripped.sections = []; // Fixes #687
+  }
   return stripped;
 }
 
diff --git a/js/usercss.js b/js/usercss.js
index deebcbbb..bfe62bb4 100644
--- a/js/usercss.js
+++ b/js/usercss.js
@@ -71,7 +71,7 @@ const usercss = (() => {
         if (!sections.length || errors && !allowErrors) {
           throw errors;
         }
-        style.sections = sections;
+        style.sections = sections || [];
         return allowErrors ? {style, errors} : style;
       });
   }
diff --git a/manage/import-export.js b/manage/import-export.js
index 1a2f1d15..7f4ed619 100644
--- a/manage/import-export.js
+++ b/manage/import-export.js
@@ -148,7 +148,9 @@ function importFromString(jsonString) {
         !item ||
         !item.name ||
         !item.name.trim() ||
-        (item.sections && !Array.isArray(item.sections))) {
+        !item.sections ||
+        !Array.isArray(item.sections)
+    ) {
       stats.invalid.names.push(`#${index}: ${limitString(item && item.name || '')}`);
       return;
     }
diff --git a/manage/manage.js b/manage/manage.js
index 741fc9bc..f6e90894 100644
--- a/manage/manage.js
+++ b/manage/manage.js
@@ -230,7 +230,7 @@ function createStyleElement({style, name}) {
   // clear the code to free up some memory
   // (note, style is already a deep copy)
   style.sourceCode = null;
-  style.sections.forEach(section => (section.code = null));
+  (style.sections || []).forEach(section => (section.code = null));
 
   const entry = parts.entry.cloneNode(true);
   entry.id = ENTRY_ID_PREFIX_RAW + style.id;
@@ -266,7 +266,7 @@ function createStyleTargetsElement({entry, style}) {
   let numTargets = 0;
   const displayed = new Set();
   for (const type of TARGET_TYPES) {
-    for (const section of style.sections) {
+    for (const section of (style.sections || [])) {
       for (const targetValue of section[type] || []) {
         if (displayed.has(targetValue)) {
           continue;