diff --git a/src/engine/helper/HL_Process.cpp b/src/engine/helper/HL_Process.cpp
index 675d6ade..1193c67e 100644
--- a/src/engine/helper/HL_Process.cpp
+++ b/src/engine/helper/HL_Process.cpp
@@ -214,15 +214,20 @@ std::string OsProcess::execCommand(const std::string& cmd)
 #include "helper/HL_String.h"
 
 std::shared_ptr<std::thread> OsProcess::asyncExecCommand(const std::string& cmdline,
-                                   std::function<void(const std::string& line)> callback,
+                                   std::function<void(const std::string& line)> line_callback,
+                                   std::function<void(const std::string& reason)> finished_callback,
                                    bool& finish_flag)
 {
-    std::shared_ptr<std::thread> t = std::make_shared<std::thread>([cmdline, callback, &finish_flag]()
+    std::shared_ptr<std::thread> t = std::make_shared<std::thread>([cmdline, line_callback, finished_callback, &finish_flag]()
     {
         std::string cp = cmdline;
         FILE* pipe = popen(cp.c_str(), "r");
         if (!pipe)
-            throw std::runtime_error("Failed to run.");
+        {
+            if (finished_callback)
+                finished_callback("Failed to open pipe");
+            return;
+        }
 
         char buffer[1024];
         std::string lines;
@@ -247,7 +252,7 @@ std::shared_ptr<std::thread> OsProcess::asyncExecCommand(const std::string& cmdl
             int r;
             do
             {
-                r = read(fno, buffer, sizeof(buffer)-1);
+                r = (int)read(fno, buffer, sizeof(buffer) - 1);
                 if (r > 0)
                 {
                     buffer[r] = 0;
@@ -256,7 +261,7 @@ std::shared_ptr<std::thread> OsProcess::asyncExecCommand(const std::string& cmdl
             }
             while (r == sizeof(buffer) - 1);
 
-            if (lines.find("\n") != std::string::npos && callback)
+            if (lines.find("\n") != std::string::npos && line_callback)
             {
                 std::string::size_type p = 0;
                 while (p < lines.size())
@@ -264,7 +269,8 @@ std::shared_ptr<std::thread> OsProcess::asyncExecCommand(const std::string& cmdl
                     std::string::size_type d = lines.find("\n", p);
                     if (d != std::string::npos)
                     {
-                        callback(StringHelper::trim(lines.substr(p, d-p)));
+                        if (line_callback)
+                            line_callback(StringHelper::trim(lines.substr(p, d-p)));
                         p = d + 1;
                     }
                 }
@@ -277,6 +283,8 @@ std::shared_ptr<std::thread> OsProcess::asyncExecCommand(const std::string& cmdl
             pclose(pipe);
 
         finish_flag = true;
+        if (finished_callback)
+            finished_callback(std::string());
     });
 
     return t;
diff --git a/src/engine/helper/HL_Process.h b/src/engine/helper/HL_Process.h
index dc14b5eb..fcd7307f 100644
--- a/src/engine/helper/HL_Process.h
+++ b/src/engine/helper/HL_Process.h
@@ -11,7 +11,8 @@ class OsProcess
 public:
     static std::string execCommand(const std::string& cmdline);
     static std::shared_ptr<std::thread> asyncExecCommand(const std::string& cmdline,
-                                   std::function<void(const std::string& line)> callback,
+                                   std::function<void(const std::string& line)> line_callback,
+                                   std::function<void(const std::string& reason)> finished_callback,
                                    bool& finish_flag);
 
 };
diff --git a/src/engine/helper/HL_Sync.cpp b/src/engine/helper/HL_Sync.cpp
index 6514a526..522e0421 100644
--- a/src/engine/helper/HL_Sync.cpp
+++ b/src/engine/helper/HL_Sync.cpp
@@ -7,6 +7,7 @@
 #include <assert.h>
 #include <atomic>
 #include <memory.h>
+#include <iostream>
 
 #ifdef TARGET_OSX
 # include <libkern/OSAtomic.h>
@@ -160,6 +161,7 @@ bool Semaphore::waitFor(int milliseconds) {
 
     if (!m_cv.wait_for(lock, std::chrono::milliseconds(milliseconds), [this]() { return m_count > 0; }))
         return false;
+
     m_count--;
     return true;
 }
@@ -224,7 +226,7 @@ size_t TimerQueue::cancel(uint64_t id) {
             newItem.handler = std::move(item.handler);
             item.handler = nullptr;
             m_items.push(std::move(newItem));
-
+            std::cout << "Cancelled timer. " << std::endl;
             lk.unlock();
             // Something changed, so wake up timer thread
             m_checkWork.notify();
@@ -263,8 +265,10 @@ void TimerQueue::run()
         {
             // Timers found, so wait until it expires (or something else
             // changes)
-            int milliseconds = std::chrono::duration_cast<std::chrono::milliseconds>(end.second - std::chrono::steady_clock::now()).count();
-            m_checkWork.waitFor(milliseconds);
+            int milliseconds = std::chrono::duration_cast<std::chrono::milliseconds>
+                    (end.second - std::chrono::steady_clock::now()).count();
+            //std::cout << "Waiting m_checkWork for " << milliseconds * 1000 << "ms." << std::endl;
+            m_checkWork.waitFor(milliseconds * 1000);
         } else {
             // No timers exist, so wait forever until something changes
             m_checkWork.wait();