diff --git a/rtgui/guiutils.cc b/rtgui/guiutils.cc
index ec0bf6588..48a01f040 100644
--- a/rtgui/guiutils.cc
+++ b/rtgui/guiutils.cc
@@ -83,59 +83,6 @@ void IdleRegister::destroy()
     mutex.unlock();
 }
 
-/*
-gboolean giveMeAGo(void* data) {
-    GThreadLock *threadMutex = static_cast<GThreadLock*>(data);
-    printf("A\n");
-    Glib::Threads::Mutex::Lock GUILock(threadMutex->GUI);
-    printf("B\n");
-    {
-    Glib::Threads::Mutex::Lock operationLock(threadMutex->operation);
-    printf("C\n");
-
-    threadMutex->operationCond.signal();
-    printf("D\n");
-    operationLock.release();  // because we're not sure that "lock" destructor happens here...
-    }
-    threadMutex->GUICond.wait(threadMutex->GUI);
-    printf("E\n");
-
-    GUILock.release();
-
-    return false;
-}
-
-GThreadLock::GThreadLock() : sameThread(false) {
-    if (Glib::Threads::Thread::self() == mainThread) {
-        sameThread = true;
-        return;
-    }
-
-    printf("10\n");
-    {
-    Glib::Threads::Mutex::Lock operationLock(operation);
-
-    printf("20\n");
-    gdk_threads_add_idle(giveMeAGo, this);
-
-    printf("30\n");
-    operationCond.wait(operation);
-    printf("40\n");
-    operationLock.release();
-    }
-}
-
-GThreadLock::~GThreadLock() {
-    if (!sameThread) {
-        printf("50\n");
-        Glib::Threads::Mutex::Lock lock(GUI);
-        printf("60\n");
-        GUICond.signal();
-        printf("Fin\n");
-    }
-}
-*/
-
 Glib::ustring escapeHtmlChars(const Glib::ustring &src)
 {
 
diff --git a/rtgui/threadutils.cc b/rtgui/threadutils.cc
index 7ba296081..4f8190c36 100644
--- a/rtgui/threadutils.cc
+++ b/rtgui/threadutils.cc
@@ -17,6 +17,7 @@
  *  along with RawTherapee.  If not, see <http://www.gnu.org/licenses/>.
  */
 #include "threadutils.h"
+#include <glibmm/threads.h>
 
 #include <csignal>
 #include <iostream>
@@ -67,7 +68,7 @@ void MyReaderLock::acquire ()
         return;
     }
 
-    Glib::Threads::Mutex::Lock lock (mutex.mutex);
+    std::lock_guard<std::mutex> lock (mutex.mutex);
 
     if (mutex.writerCount == 0) {
         // There's no writer operating, we can increment the writer count which will lock writers.
@@ -95,7 +96,7 @@ void MyReaderLock::release ()
         return;
     }
 
-    Glib::Threads::Mutex::Lock lock (mutex.mutex);
+    std::lock_guard<std::mutex> lock (mutex.mutex);
 
     // decrement the writer number first...
     --mutex.readerCount;
@@ -105,7 +106,7 @@ void MyReaderLock::release ()
         --mutex.writerCount;
 
         // ...and signal the next waiting reader/writer that it's free
-        mutex.cond.broadcast ();
+        mutex.cond.notify_one();  // notify_all ?
     }
 
     locked = false;
@@ -117,7 +118,7 @@ void MyWriterLock::acquire ()
         return;
     }
 
-    Glib::Threads::Mutex::Lock lock (mutex.mutex);
+    std::lock_guard<std::mutex> lock (mutex.mutex);
 
     // The writer count is not zero, so we have to wait for it to be zero again...
     while (mutex.writerCount != 0) {
@@ -136,12 +137,12 @@ void MyWriterLock::release ()
         return;
     }
 
-    Glib::Threads::Mutex::Lock lock (mutex.mutex);
+    std::lock_guard<std::mutex> lock (mutex.mutex);
 
     // Decrement the writer number first...
     if (--mutex.writerCount == 0) {
         // ...and if the writer count is zero again, we can wake up the next writer or reader.
-        mutex.cond.broadcast ();
+        mutex.cond.notify_one();  // notify_all ?
     }
 
     locked = false;
@@ -170,7 +171,7 @@ void MyReaderLock::acquire (const char* file, int line)
 
     trace (file, line) << "Acquiring MyReaderLock..." << std::endl;
 
-    Glib::Threads::Mutex::Lock lock (mutex.mutex);
+    std::lock_guard<std::mutex> lock (mutex.mutex);
 
     if (mutex.writerCount == 0) {
         // There's no writer operating, we can increment the writer count which will lock writers.
@@ -211,7 +212,7 @@ void MyReaderLock::release (const char* file, int line)
 
     trace (file, line) << "Releasing MyReaderLock..." << std::endl;
 
-    Glib::Threads::Mutex::Lock lock (mutex.mutex);
+    std::lock_guard<std::mutex> lock (mutex.mutex);
 
     // decrement the writer number first...
     --mutex.readerCount;
@@ -221,7 +222,7 @@ void MyReaderLock::release (const char* file, int line)
         --mutex.writerCount;
 
         // ...and signal the next waiting reader/writer that it's free
-        mutex.cond.broadcast ();
+        mutex.cond.notify_one();  // notify_all ?
 
         mutex.ownerThread = nullptr;
         mutex.lastWriterFile = "";
@@ -241,7 +242,7 @@ void MyWriterLock::acquire (const char* file, int line)
 
     trace (file, line) << "Acquiring MyWriterLock..." << std::endl;
 
-    Glib::Threads::Mutex::Lock lock (mutex.mutex);
+    std::lock_guard<std::mutex> lock (mutex.mutex);
 
     // The writer count is not zero, so we have to wait for it to be zero again...
     while (mutex.writerCount != 0) {
@@ -273,12 +274,12 @@ void MyWriterLock::release (const char* file, int line)
 
     trace (file, line) << "Releasing MyWriterLock..." << std::endl;
 
-    Glib::Threads::Mutex::Lock lock (mutex.mutex);
+    std::lock_guard<std::mutex> lock (mutex.mutex);
 
     // Decrement the writer number first...
     if (--mutex.writerCount == 0) {
         // ...and if the writer count is zero again, we can wake up the next writer or reader.
-        mutex.cond.broadcast ();
+        mutex.cond.notify_one();  // notify_all ?
 
         mutex.ownerThread = nullptr;
         mutex.lastWriterFile = "";
diff --git a/rtgui/threadutils.h b/rtgui/threadutils.h
index 1215d53a1..f54cbb845 100644
--- a/rtgui/threadutils.h
+++ b/rtgui/threadutils.h
@@ -25,14 +25,14 @@
 //#undef STRICT_MUTEX
 //#define STRICT_MUTEX 1
 
-#include <glibmm/threads.h>
-
+#include <mutex>
+#include <condition_variable>
 #include "../rtengine/noncopyable.h"
 
 #if STRICT_MUTEX && NDEBUG
-using MyMutexBase = Glib::Threads::Mutex;
+using MyMutexBase = std::mutex;
 #else
-using MyMutexBase = Glib::Threads::RecMutex;
+using MyMutexBase = std::recursive_mutex;
 #endif
 
 /**
@@ -67,8 +67,6 @@ class MyMutex::MyLock :
 {
 public:
     explicit MyLock (MyMutex& mutex);
-    MyLock (MyMutex& mutex, Glib::Threads::NotLock);
-    MyLock (MyMutex& mutex, Glib::Threads::TryLock);
 
     ~MyLock ();
 
@@ -92,8 +90,8 @@ public:
     friend class MyWriterLock;
 
 private:
-    Glib::Threads::Mutex mutex;
-    Glib::Threads::Cond cond;
+    std::mutex mutex;
+    std::condition_variable_any cond;
 
     std::size_t writerCount = 0;
     std::size_t readerCount = 0;
@@ -168,7 +166,7 @@ inline void MyMutex::lock ()
 
 inline bool MyMutex::trylock ()
 {
-    if (MyMutexBase::trylock ()) {
+    if (MyMutexBase::try_lock ()) {
 #if STRICT_MUTEX && !NDEBUG
         checkLock ();
 #endif
@@ -195,18 +193,6 @@ inline MyMutex::MyLock::MyLock (MyMutex& mutex)
     mutex.lock();
 }
 
-inline MyMutex::MyLock::MyLock (MyMutex& mutex, Glib::Threads::NotLock)
-    : mutex (mutex)
-    , locked (false)
-{
-}
-
-inline MyMutex::MyLock::MyLock (MyMutex& mutex, Glib::Threads::TryLock)
-    : mutex (mutex)
-    , locked (mutex.trylock ())
-{
-}
-
 inline MyMutex::MyLock::~MyLock ()
 {
     if (locked) {
diff --git a/rtgui/thumbimageupdater.cc b/rtgui/thumbimageupdater.cc
index c0df751a5..590a7ae1c 100644
--- a/rtgui/thumbimageupdater.cc
+++ b/rtgui/thumbimageupdater.cc
@@ -83,9 +83,9 @@ public:
 
     Glib::ThreadPool* threadPool_;
 
-    // Need to be a Glib::Threads::Mutex because used in a Glib::Threads::Cond object...
+    // Need to be a std::mutex because used in a std::condition_variable_any object...
     // This is the only exceptions along with GThreadMutex (guiutils.cc), MyMutex is used everywhere else
-    Glib::Threads::Mutex mutex_;
+    std::mutex mutex_;
 
     JobList jobs_;
 
@@ -93,7 +93,7 @@ public:
 
     bool inactive_waiting_;
 
-    Glib::Threads::Cond inactive_;
+    std::condition_variable_any inactive_;
 
     void
     processNextJob()
@@ -101,7 +101,7 @@ public:
         Job j;
 
         {
-            Glib::Threads::Mutex::Lock lock(mutex_);
+            std::lock_guard<std::mutex> lock(mutex_);
 
             // nothing to do; could be jobs have been removed
             if ( jobs_.empty() ) {
@@ -164,10 +164,10 @@ public:
         }
 
         if ( --active_ == 0 ) {
-            Glib::Threads::Mutex::Lock lock(mutex_);
+            std::lock_guard<std::mutex> lock(mutex_);
             if (inactive_waiting_) {
                 inactive_waiting_ = false;
-                inactive_.broadcast();
+                inactive_.notify_one();  // notify_all ?
             }
         }
     }
@@ -196,7 +196,7 @@ void ThumbImageUpdater::add(ThumbBrowserEntryBase* tbe, bool* priority, bool upg
         return;
     }
 
-    Glib::Threads::Mutex::Lock lock(impl_->mutex_);
+    std::lock_guard<std::mutex> lock(impl_->mutex_);
 
     // look up if an older version is in the queue
     Impl::JobList::iterator i(impl_->jobs_.begin());
@@ -228,7 +228,7 @@ void ThumbImageUpdater::removeJobs(ThumbImageUpdateListener* listener)
     DEBUG("removeJobs(%p)", listener);
 
     {
-        Glib::Threads::Mutex::Lock lock(impl_->mutex_);
+        std::lock_guard<std::mutex> lock(impl_->mutex_);
 
         for( Impl::JobList::iterator i(impl_->jobs_.begin()); i != impl_->jobs_.end(); ) {
             if (i->listener_ == listener) {
@@ -244,7 +244,7 @@ void ThumbImageUpdater::removeJobs(ThumbImageUpdateListener* listener)
     while ( impl_->active_ != 0 ) {
         DEBUG("waiting for running jobs1");
         {
-            Glib::Threads::Mutex::Lock lock(impl_->mutex_);
+            std::lock_guard<std::mutex> lock(impl_->mutex_);
             impl_->inactive_waiting_ = true;
             impl_->inactive_.wait(impl_->mutex_);
         }
@@ -256,7 +256,7 @@ void ThumbImageUpdater::removeAllJobs()
     DEBUG("stop");
 
     {
-        Glib::Threads::Mutex::Lock lock(impl_->mutex_);
+        std::lock_guard<std::mutex> lock(impl_->mutex_);
 
         impl_->jobs_.clear();
     }
@@ -264,7 +264,7 @@ void ThumbImageUpdater::removeAllJobs()
     while ( impl_->active_ != 0 ) {
         DEBUG("waiting for running jobs2");
         {
-            Glib::Threads::Mutex::Lock lock(impl_->mutex_);
+            std::lock_guard<std::mutex> lock(impl_->mutex_);
             impl_->inactive_waiting_ = true;
             impl_->inactive_.wait(impl_->mutex_);
         }