Index: src/solid/devices/backends/win/winstoragevolume.cpp
===================================================================
--- src/solid/devices/backends/win/winstoragevolume.cpp
+++ src/solid/devices/backends/win/winstoragevolume.cpp
@@ -21,6 +21,7 @@
 #include "winstoragevolume.h"
 
 #include "windevicemanager.h"
+#include "winutils_p.h"
 
 #include <qt_windows.h>
 
@@ -61,6 +62,9 @@
     dLetter[dLetterSize] = (wchar_t)'\\';
     dLetter[dLetterSize + 1] = 0;
 
+    // block error dialogs from GetDiskFreeSpaceEx & other WinAPI, see bug 371012
+    WinErrorBlocker block;
+
     if (GetVolumeInformation(dLetter, label, MAX_PATH, &serial, NULL, &flags, fs, MAX_PATH)) {
         m_label = QString::fromWCharArray(label);
         m_fs = QString::fromWCharArray(fs);
Index: src/solid/devices/backends/win/winutils_p.h
===================================================================
--- /dev/null
+++ src/solid/devices/backends/win/winutils_p.h
@@ -0,0 +1,67 @@
+/*
+    Copyright 2016 Kevin Funk <kfunk@kde.org>
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Lesser General Public
+    License as published by the Free Software Foundation; either
+    version 2.1 of the License, or (at your option) version 3, or any
+    later version accepted by the membership of KDE e.V. (or its
+    successor approved by the membership of KDE e.V.), which shall
+    act as a proxy defined in Section 6 of version 3 of the license.
+
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public
+    License along with this library. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef WINUTILS_P_H
+#define WINUTILS_P_H
+
+#include "windevicemanager.h" // for qGetLastError
+
+#include <qt_windows.h>
+
+/**
+ * @brief RAII class for blocking Windows from reporting errors
+ *
+ * Internally calls GetThreadErrorMode + SetErrorMode. This class stores the
+ * current error mode on construction and disables certain error reportings
+ * during the life time of this object
+ *
+ * @code
+ * {
+ *     WinErrorBlocker blocker; // custom error mode is set
+ *     // Your Windows API calls...
+ * } // end of scope: original error mode is restored
+ * @endcode
+ *
+ * Note that qstorageinfo_win.cpp (qtbase) does something similar to silence errors
+ *
+ * See MSDN documentation: https://msdn.microsoft.com/en-us/library/windows/desktop/dd553630(v=vs.85).aspx
+ */
+class WinErrorBlocker
+{
+public:
+    WinErrorBlocker()
+    {
+        if (!::SetThreadErrorMode(SEM_FAILCRITICALERRORS | SEM_NOOPENFILEERRORBOX, &m_oldmode)) {
+            qWarning() << "Failed to call SetThreadErrorMode:" << qGetLastError();
+        }
+    }
+    ~WinErrorBlocker()
+    {
+        if (!::SetThreadErrorMode(m_oldmode, NULL)) {
+            qWarning() << "Failed to call SetThreadErrorMode:" << qGetLastError();
+        }
+    }
+
+private:
+    Q_DISABLE_COPY(WinErrorBlocker)
+    DWORD m_oldmode;
+};
+
+#endif