diff --git a/src/plugins/clearcase/clearcaseplugin.cpp b/src/plugins/clearcase/clearcaseplugin.cpp
index 524c430837a..cb9445bbce3 100644
--- a/src/plugins/clearcase/clearcaseplugin.cpp
+++ b/src/plugins/clearcase/clearcaseplugin.cpp
@@ -1657,7 +1657,7 @@ bool ClearCasePlugin::vcsOpen(const QString &workingDir, const QString &fileName
         }
 
         foreach (DocumentModel::Entry *e, DocumentModel::entries()) {
-            if (e->fileName() == absPath) {
+            if (e->fileName().toString() == absPath) {
                 e->document->checkPermissions();
                 break;
             }
diff --git a/src/plugins/coreplugin/editormanager/documentmodel.cpp b/src/plugins/coreplugin/editormanager/documentmodel.cpp
index 625f7aba84d..e4c51f5838e 100644
--- a/src/plugins/coreplugin/editormanager/documentmodel.cpp
+++ b/src/plugins/coreplugin/editormanager/documentmodel.cpp
@@ -66,7 +66,7 @@ public:
     void addEntry(DocumentModel::Entry *entry);
     void removeDocument(int idx);
 
-    int indexOfFilePath(const QString &filePath) const;
+    int indexOfFilePath(const Utils::FileName &filePath) const;
     int indexOfDocument(IDocument *document) const;
 
 private slots:
@@ -128,9 +128,9 @@ QAbstractItemModel *DocumentModel::model()
     return d;
 }
 
-QString DocumentModel::Entry::fileName() const
+Utils::FileName DocumentModel::Entry::fileName() const
 {
-    return document ? document->filePath().toString() : m_fileName;
+    return document ? document->filePath() : m_fileName;
 }
 
 QString DocumentModel::Entry::displayName() const
@@ -177,7 +177,7 @@ void DocumentModel::addEditor(IEditor *editor, bool *isNewDocument)
 void DocumentModel::addRestoredDocument(const QString &fileName, const QString &displayName, Id id)
 {
     Entry *entry = new Entry;
-    entry->m_fileName = fileName;
+    entry->m_fileName = Utils::FileName::fromString(fileName);
     entry->m_displayName = displayName;
     entry->m_id = id;
     d->addEntry(entry);
@@ -190,10 +190,8 @@ DocumentModel::Entry *DocumentModel::firstRestoredEntry()
 
 void DocumentModelPrivate::addEntry(DocumentModel::Entry *entry)
 {
-    QString fileName = entry->fileName();
-
     // replace a non-loaded entry (aka 'restored') if possible
-    int previousIndex = indexOfFilePath(fileName);
+    int previousIndex = indexOfFilePath(entry->fileName());
     if (previousIndex >= 0) {
         if (entry->document && m_entries.at(previousIndex)->document == 0) {
             DocumentModel::Entry *previousEntry = m_entries.at(previousIndex);
@@ -220,13 +218,14 @@ void DocumentModelPrivate::addEntry(DocumentModel::Entry *entry)
     endInsertRows();
 }
 
-int DocumentModelPrivate::indexOfFilePath(const QString &filePath) const
+int DocumentModelPrivate::indexOfFilePath(const Utils::FileName &filePath) const
 {
     if (filePath.isEmpty())
         return -1;
-    const QString fixedPath = DocumentManager::fixFileName(filePath, DocumentManager::ResolveLinks);
+    const QString fixedPath = DocumentManager::fixFileName(filePath.toString(),
+                                                           DocumentManager::ResolveLinks);
     return Utils::indexOf(m_entries, [&fixedPath](DocumentModel::Entry *entry) {
-        return DocumentManager::fixFileName(entry->fileName(),
+        return DocumentManager::fixFileName(entry->fileName().toString(),
                                             DocumentManager::ResolveLinks) == fixedPath;
     });
 }
@@ -256,7 +255,7 @@ void DocumentModel::removeEditor(IEditor *editor, bool *lastOneForDocument)
 
 void DocumentModel::removeDocument(const QString &fileName)
 {
-    int index = d->indexOfFilePath(fileName);
+    int index = d->indexOfFilePath(Utils::FileName::fromString(fileName));
     QTC_ASSERT(!d->m_entries.at(index)->document, return); // we wouldn't know what to do with the associated editors
     d->removeDocument(index);
 }
@@ -330,7 +329,7 @@ QList<IDocument *> DocumentModel::openedDocuments()
 
 IDocument *DocumentModel::documentForFilePath(const QString &filePath)
 {
-    const int index = d->indexOfFilePath(filePath);
+    const int index = d->indexOfFilePath(Utils::FileName::fromString(filePath));
     if (index < 0)
         return 0;
     return d->m_entries.at(index)->document;
@@ -403,13 +402,13 @@ QVariant DocumentModelPrivate::data(const QModelIndex &index, int role) const
         if (e->document)
             showLock = e->document->filePath().isEmpty() ? false : e->document->isFileReadOnly();
         else
-            showLock = !QFileInfo(e->m_fileName).isWritable();
+            showLock = !e->m_fileName.toFileInfo().isWritable();
         return showLock ? m_lockedIcon : QIcon();
     }
     case Qt::ToolTipRole:
         return e->fileName().isEmpty()
                 ? e->displayName()
-                : QDir::toNativeSeparators(e->fileName());
+                : e->fileName().toUserOutput();
     default:
         return QVariant();
     }
@@ -431,7 +430,7 @@ QMimeData *DocumentModelPrivate::mimeData(const QModelIndexList &indexes) const
         const DocumentModel::Entry *e = DocumentModel::entryAtRow(index.row());
         if (!e || e->fileName().isEmpty())
             continue;
-        data->addFile(e->fileName());
+        data->addFile(e->fileName().toString());
     }
     return data;
 }
diff --git a/src/plugins/coreplugin/editormanager/documentmodel.h b/src/plugins/coreplugin/editormanager/documentmodel.h
index 94c87c79028..8b5f286a66c 100644
--- a/src/plugins/coreplugin/editormanager/documentmodel.h
+++ b/src/plugins/coreplugin/editormanager/documentmodel.h
@@ -34,6 +34,8 @@
 #include "../core_global.h"
 #include "../id.h"
 
+#include <utils/fileutils.h>
+
 #include <QAbstractItemModel>
 
 QT_FORWARD_DECLARE_CLASS(QIcon)
@@ -57,10 +59,10 @@ public:
     struct CORE_EXPORT Entry {
         Entry();
         IDocument *document;
-        QString fileName() const;
+        Utils::FileName fileName() const;
         QString displayName() const;
         Id id() const;
-        QString m_fileName;
+        Utils::FileName m_fileName;
         QString m_displayName;
         Id m_id;
     };
diff --git a/src/plugins/coreplugin/editormanager/editormanager.cpp b/src/plugins/coreplugin/editormanager/editormanager.cpp
index b31b2a71102..ea4ab162569 100644
--- a/src/plugins/coreplugin/editormanager/editormanager.cpp
+++ b/src/plugins/coreplugin/editormanager/editormanager.cpp
@@ -1049,7 +1049,7 @@ void EditorManagerPrivate::activateEditorForEntry(EditorView *view, DocumentMode
         return;
     }
 
-    if (!openEditor(view, entry->fileName(), entry->id(), flags))
+    if (!openEditor(view, entry->fileName().toString(), entry->id(), flags))
         DocumentModel::removeEntry(entry);
 }
 
@@ -1593,8 +1593,7 @@ void EditorManagerPrivate::copyFilePathFromContextMenu()
 {
     if (!d->m_contextMenuEntry)
         return;
-    QApplication::clipboard()->setText(FileName::fromString(
-                                           d->m_contextMenuEntry->fileName()).toUserOutput());
+    QApplication::clipboard()->setText(d->m_contextMenuEntry->fileName().toUserOutput());
 }
 
 void EditorManagerPrivate::copyLocationFromContextMenu()
@@ -1602,9 +1601,8 @@ void EditorManagerPrivate::copyLocationFromContextMenu()
     const QAction *action = qobject_cast<const QAction *>(sender());
     if (!d->m_contextMenuEntry || !action)
         return;
-    const QString text =
-        FileName::fromString(d->m_contextMenuEntry->fileName()).toUserOutput()
-        + QLatin1Char(':') + action->data().toString();
+    const QString text = d->m_contextMenuEntry->fileName().toUserOutput()
+            + QLatin1Char(':') + action->data().toString();
     QApplication::clipboard()->setText(text);
 }
 
@@ -1612,7 +1610,7 @@ void EditorManagerPrivate::copyFileNameFromContextMenu()
 {
     if (!d->m_contextMenuEntry)
         return;
-    QApplication::clipboard()->setText(FileName::fromString(d->m_contextMenuEntry->fileName()).fileName());
+    QApplication::clipboard()->setText(d->m_contextMenuEntry->fileName().fileName());
 }
 
 void EditorManagerPrivate::saveDocumentFromContextMenu()
@@ -1766,21 +1764,21 @@ void EditorManagerPrivate::showInGraphicalShell()
 {
     if (!d->m_contextMenuEntry || d->m_contextMenuEntry->fileName().isEmpty())
         return;
-    FileUtils::showInGraphicalShell(ICore::mainWindow(), d->m_contextMenuEntry->fileName());
+    FileUtils::showInGraphicalShell(ICore::mainWindow(), d->m_contextMenuEntry->fileName().toString());
 }
 
 void EditorManagerPrivate::openTerminal()
 {
     if (!d->m_contextMenuEntry || d->m_contextMenuEntry->fileName().isEmpty())
         return;
-    FileUtils::openTerminal(QFileInfo(d->m_contextMenuEntry->fileName()).path());
+    FileUtils::openTerminal(d->m_contextMenuEntry->fileName().parentDir().toString());
 }
 
 void EditorManagerPrivate::findInDirectory()
 {
     if (!d->m_contextMenuEntry || d->m_contextMenuEntry->fileName().isEmpty())
         return;
-    emit m_instance->findOnFileSystemRequest(QFileInfo(d->m_contextMenuEntry->fileName()).path());
+    emit m_instance->findOnFileSystemRequest(d->m_contextMenuEntry->fileName().parentDir().toString());
 }
 
 void EditorManagerPrivate::split(Qt::Orientation orientation)
@@ -1927,7 +1925,7 @@ void EditorManager::addSaveAndCloseEditorActions(QMenu *contextMenu, DocumentMod
     d->m_contextMenuEntry = entry;
     d->m_contextMenuEditor = editor;
 
-    const QString filePath = entry ? entry->fileName() : QString();
+    const FileName filePath = entry ? entry->fileName() : FileName();
     const bool copyActionsEnabled = !filePath.isEmpty();
     d->m_copyFilePathContextAction->setEnabled(copyActionsEnabled);
     d->m_copyLocationContextAction->setEnabled(copyActionsEnabled);
@@ -1993,7 +1991,7 @@ void EditorManager::addNativeDirAndOpenWithActions(QMenu *contextMenu, DocumentM
             DocumentManager::instance(), SLOT(executeOpenWithMenuAction(QAction*)));
     openWith->setEnabled(enabled);
     if (enabled)
-        DocumentManager::populateOpenWithMenu(openWith, entry->fileName());
+        DocumentManager::populateOpenWithMenu(openWith, entry->fileName().toString());
 }
 
 void EditorManager::saveDocument()
@@ -2339,7 +2337,7 @@ IEditor *EditorManager::openEditorWithContents(Id editorId,
             int i = 1;
             QSet<QString> docnames;
             foreach (DocumentModel::Entry *entry, DocumentModel::entries()) {
-                QString name = entry->fileName();
+                QString name = entry->fileName().toString();
                 if (name.isEmpty())
                     name = entry->displayName();
                 else
@@ -2485,7 +2483,7 @@ QByteArray EditorManager::saveState()
 
     foreach (DocumentModel::Entry *entry, entries) {
         if (!entry->document || !entry->document->isTemporary())
-            stream << entry->fileName() << entry->displayName() << entry->id();
+            stream << entry->fileName().toString() << entry->displayName() << entry->id();
     }
 
     stream << d->m_editorAreas.first()->saveState(); // TODO
diff --git a/src/plugins/coreplugin/editormanager/openeditorswindow.cpp b/src/plugins/coreplugin/editormanager/openeditorswindow.cpp
index eab67b2a7a7..29962c596f2 100644
--- a/src/plugins/coreplugin/editormanager/openeditorswindow.cpp
+++ b/src/plugins/coreplugin/editormanager/openeditorswindow.cpp
@@ -254,7 +254,7 @@ void OpenEditorsWindow::addRestoredItems()
         QString title = entry->displayName();
         item->setIcon(0, m_emptyIcon);
         item->setText(0, title);
-        item->setToolTip(0, entry->fileName());
+        item->setToolTip(0, entry->fileName().toString());
         item->setData(0, Qt::UserRole+2, QVariant::fromValue(entry->id()));
         item->setTextAlignment(0, Qt::AlignLeft);
 
diff --git a/src/plugins/coreplugin/editortoolbar.cpp b/src/plugins/coreplugin/editortoolbar.cpp
index 1c8a0105f2f..0806a254631 100644
--- a/src/plugins/coreplugin/editortoolbar.cpp
+++ b/src/plugins/coreplugin/editortoolbar.cpp
@@ -455,7 +455,7 @@ bool EditorToolBar::eventFilter(QObject *obj, QEvent *event)
                 return Utils::StyledBar::eventFilter(obj, event);
             auto drag = new QDrag(this);
             auto data = new Utils::FileDropMimeData;
-            data->addFile(entry->fileName());
+            data->addFile(entry->fileName().toString());
             drag->setMimeData(data);
             Qt::DropAction action = drag->exec(Qt::MoveAction | Qt::CopyAction, Qt::MoveAction);
             if (action == Qt::MoveAction)
diff --git a/src/plugins/coreplugin/locator/opendocumentsfilter.cpp b/src/plugins/coreplugin/locator/opendocumentsfilter.cpp
index 433f8cc3a56..8be5d2b6662 100644
--- a/src/plugins/coreplugin/locator/opendocumentsfilter.cpp
+++ b/src/plugins/coreplugin/locator/opendocumentsfilter.cpp
@@ -73,7 +73,7 @@ QList<LocatorFilterEntry> OpenDocumentsFilter::matchesFor(QFutureInterface<Locat
     foreach (const DocumentModel::Entry &editorEntry, editors()) {
         if (future.isCanceled())
             break;
-        QString fileName = editorEntry.fileName();
+        QString fileName = editorEntry.fileName().toString();
         if (fileName.isEmpty())
             continue;
         QString displayName = editorEntry.displayName();
diff --git a/src/plugins/cpptools/cppincludesfilter.cpp b/src/plugins/cpptools/cppincludesfilter.cpp
index 1ed1d19c375..89855d7031a 100644
--- a/src/plugins/cpptools/cppincludesfilter.cpp
+++ b/src/plugins/cpptools/cppincludesfilter.cpp
@@ -168,7 +168,7 @@ void CppIncludesFilter::prepareSearch(const QString &entry)
         }
         foreach (DocumentModel::Entry *entry, DocumentModel::entries()) {
             if (entry)
-                seedPaths.insert(entry->fileName());
+                seedPaths.insert(entry->fileName().toString());
         }
         CPlusPlus::Snapshot snapshot = CppModelManager::instance()->snapshot();
         setFileIterator(new CppIncludesIterator(snapshot, seedPaths));
diff --git a/src/plugins/texteditor/findinopenfiles.cpp b/src/plugins/texteditor/findinopenfiles.cpp
index 457861ccaf5..200dd192346 100644
--- a/src/plugins/texteditor/findinopenfiles.cpp
+++ b/src/plugins/texteditor/findinopenfiles.cpp
@@ -71,7 +71,7 @@ Utils::FileIterator *FindInOpenFiles::files(const QStringList &nameFilters,
     QList<QTextCodec *> codecs;
     foreach (Core::DocumentModel::Entry *entry,
              Core::DocumentModel::entries()) {
-        QString fileName = entry->fileName();
+        QString fileName = entry->fileName().toString();
         if (!fileName.isEmpty()) {
             fileNames.append(fileName);
             QTextCodec *codec = openEditorEncodings.value(fileName);