diff --git a/code/ryzom/tools/client/ryzom_installer/src/downloader.cpp b/code/ryzom/tools/client/ryzom_installer/src/downloader.cpp
index bbc660f8a..19e5793ee 100644
--- a/code/ryzom/tools/client/ryzom_installer/src/downloader.cpp
+++ b/code/ryzom/tools/client/ryzom_installer/src/downloader.cpp
@@ -272,6 +272,8 @@ void CDownloader::onHeadFinished()
 	{
 		if (redirection.isEmpty())
 		{
+			nlwarning("No redirection defined");
+
 			if (m_listener) m_listener->operationFail(tr("Redirection URL is not defined"));
 			return;
 		}
@@ -298,6 +300,8 @@ void CDownloader::onHeadFinished()
 
 		if (!m_supportsAcceptRanges && acceptRanges == "bytes")
 		{
+			nlinfo("Server supports resume for %s", Q2C(url));
+
 			// server supports resume, part 1
 			m_supportsAcceptRanges = true;
 
@@ -309,6 +313,7 @@ void CDownloader::onHeadFinished()
 		// server doesn't support resume or
 		// we requested range, but server always returns 200
 		// download from the beginning
+		nlwarning("Server doesn't support resume, download %s from the beginning", Q2C(url));
 	}
 	
 	// we requested with a range
@@ -327,10 +332,12 @@ void CDownloader::onHeadFinished()
 
 			// update offset and size
 			if (m_listener) m_listener->operationInit(m_offset, m_size);
+
+			nlinfo("Server supports resume for %s: offset %" NL_I64 "d, size %" NL_I64 "d", Q2C(url), m_offset, m_size);
 		}
 		else
 		{
-			qDebug() << "Unable to parse";
+			nlwarning("Unable to parse %s", Q2C(contentRange));
 		}
 	}
 
diff --git a/code/ryzom/tools/client/ryzom_installer/src/installdialog.cpp b/code/ryzom/tools/client/ryzom_installer/src/installdialog.cpp
index 65378c369..b1ef5de67 100644
--- a/code/ryzom/tools/client/ryzom_installer/src/installdialog.cpp
+++ b/code/ryzom/tools/client/ryzom_installer/src/installdialog.cpp
@@ -132,17 +132,18 @@ void CInstallDialog::accept()
 	// check free disk space
 	qint64 freeSpace = NLMISC::CSystemInfo::availableHDSpace(m_dstDirectory.toUtf8().constData());
 
+	// shouldn't happen
 	if (freeSpace == 0)
 	{
-		QString error = qFromUtf8(NLMISC::formatErrorMessage(NLMISC::getLastError()));
+		int error = NLMISC::getLastError();
 
-		QMessageBox::StandardButton res = QMessageBox::warning(this, tr("Error"), tr("Error '%1' occured when trying to check free disk space on %2.").arg(error).arg(m_dstDirectory));
-		return;
+		nlwarning("Error '%s' (%d) occured when trying to check free disk space on %s, continue anyway", NLMISC::formatErrorMessage(error).c_str(), error, Q2C(m_dstDirectory));
 	}
 
 	const CServer &server = CConfigFile::getInstance()->getServer();
 
-	if (freeSpace < server.dataUncompressedSize)
+	// compare with exact size of current directory
+	if (freeSpace && freeSpace < server.dataUncompressedSize)
 	{
 		QMessageBox::StandardButton res = QMessageBox::warning(this, tr("Not enough free disk space"), tr("You don't have enough free space on this disk, please make more space or choose a directory on another disk."));
 		return;
diff --git a/code/ryzom/tools/client/ryzom_installer/src/main.cpp b/code/ryzom/tools/client/ryzom_installer/src/main.cpp
index 3420ef42e..47201a807 100644
--- a/code/ryzom/tools/client/ryzom_installer/src/main.cpp
+++ b/code/ryzom/tools/client/ryzom_installer/src/main.cpp
@@ -152,6 +152,11 @@ int main(int argc, char *argv[])
 		return 1;
 	}
 
+	// init log
+	CLogHelper logHelper(config.getInstallationDirectory());
+
+	nlinfo("Launched %s", Q2C(config.getInstallerCurrentFilePath()));
+
 #if defined(Q_OS_WIN) && !defined(_DEBUG)
 	// under Windows, Ryzom Installer should always be copied in TEMP directory
 	QString tempPath = QStandardPaths::writableLocation(QStandardPaths::TempLocation);
@@ -159,6 +164,8 @@ int main(int argc, char *argv[])
 	// check if launched from TEMP directory
 	if (step == Done && !config.getInstallerCurrentDirPath().startsWith(tempPath))
 	{
+		nlinfo("Not launched from TEMP directory");
+
 		// try to delete all temporary installers
 		QDir tempDir(tempPath);
 
@@ -173,17 +180,25 @@ int main(int argc, char *argv[])
 			QDir dirToRemove(tempDir);
 			dirToRemove.cd(dir);
 			dirToRemove.removeRecursively();
+
+			nlinfo("Delete directory %s", Q2C(dir));
 		}
 
 		tempPath += QString("/ryzom_installer_%1").arg(QDateTime::currentMSecsSinceEpoch());
 
+		nlinfo("Creating directory %s", Q2C(tempPath));
+
 		// copy installer and required files to TEMP directory
 		if (QDir().mkdir(tempPath) && copyInstallerFiles(config.getInstallerRequiredFiles(), tempPath))
 		{
 			QString tempFile = tempPath + "/" + QFileInfo(config.getInstallerCurrentFilePath()).fileName();
 
+			nlinfo("Launching %s", Q2C(tempFile));
+
 			// launch copy in TEMP directory with same arguments
 			if (QProcess::startDetached(tempFile, QApplication::arguments())) return 0;
+
+			nlwarning("Unable to launch %s", Q2C(tempFile));
 		}
 	}
 #endif
@@ -193,6 +208,8 @@ int main(int argc, char *argv[])
 
 	if (parser.isSet(uninstallOption))
 	{
+		nlinfo("Uninstalling...");
+
 		SComponents components;
 
 		// add all servers by default
@@ -227,6 +244,8 @@ int main(int argc, char *argv[])
 
 	if (step == ShowMigrateWizard)
 	{
+		nlinfo("Display migration dialog");
+
 		CMigrateDialog dialog;
 
 		if (!dialog.exec()) return 1;
@@ -235,6 +254,8 @@ int main(int argc, char *argv[])
 	}
 	else if (step == ShowInstallWizard)
 	{
+		nlinfo("Display installation dialog");
+
 		CInstallDialog dialog;
 
 		if (!dialog.exec()) return 1;
@@ -242,6 +263,8 @@ int main(int argc, char *argv[])
 		step = config.getInstallNextStep();
 	}
 
+	nlinfo("Next step is %s", Q2C(stepToString(step)));
+
 	bool restartInstaller = false;
 	
 	if (step != Done)
@@ -254,6 +277,8 @@ int main(int argc, char *argv[])
 
 		step = config.getInstallNextStep();
 
+		nlinfo("Last step is %s", Q2C(stepToString(step)));
+
 		if (step == LaunchInstalledInstaller)
 		{
 			// restart more recent installed Installer version
@@ -271,6 +296,8 @@ int main(int argc, char *argv[])
 	if (restartInstaller)
 	{
 #ifndef _DEBUG
+		nlinfo("Restart Installer %s", Q2C(config.getInstallerInstalledFilePath()));
+
 #ifndef Q_OS_WIN32
 		// fix executable permissions under UNIX
 		QFile::setPermissions(config.getInstallerInstalledFilePath(), QFile::permissions(config.getInstallerInstalledFilePath()) | QFile::ExeGroup | QFile::ExeUser | QFile::ExeOther);
diff --git a/code/ryzom/tools/client/ryzom_installer/src/migratedialog.cpp b/code/ryzom/tools/client/ryzom_installer/src/migratedialog.cpp
index 5f645042a..0aec91d09 100644
--- a/code/ryzom/tools/client/ryzom_installer/src/migratedialog.cpp
+++ b/code/ryzom/tools/client/ryzom_installer/src/migratedialog.cpp
@@ -147,16 +147,16 @@ void CMigrateDialog::accept()
 	// check free disk space
 	qint64 freeSpace = NLMISC::CSystemInfo::availableHDSpace(m_dstDirectory.toUtf8().constData());
 
+	// shouldn't happen
 	if (freeSpace == 0)
 	{
-		QString error = qFromUtf8(NLMISC::formatErrorMessage(NLMISC::getLastError()));
+		int error = NLMISC::getLastError();
 
-		QMessageBox::StandardButton res = QMessageBox::warning(this, tr("Error"), tr("Error '%1' occured when trying to check free disk space on %2.").arg(error).arg(m_dstDirectory));
-		return;
+		nlwarning("Error '%s' (%d) occured when trying to check free disk space on %s, continue anyway", NLMISC::formatErrorMessage(error).c_str(), error, Q2C(m_dstDirectory));
 	}
 
 	// compare with exact size of current directory
-	if (freeSpace < getDirectorySize(m_currentDirectory, true))
+	if (freeSpace && freeSpace < getDirectorySize(m_currentDirectory, true))
 	{
 		QMessageBox::StandardButton res = QMessageBox::warning(this, tr("Not enough free disk space"), tr("You don't have enough free space on this disk, please make more space or choose a directory on another disk."));
 		return;
diff --git a/code/ryzom/tools/client/ryzom_installer/src/operation.h b/code/ryzom/tools/client/ryzom_installer/src/operation.h
index 71627363e..341e93a74 100644
--- a/code/ryzom/tools/client/ryzom_installer/src/operation.h
+++ b/code/ryzom/tools/client/ryzom_installer/src/operation.h
@@ -73,6 +73,8 @@ enum OperationStep
 	Done
 };
 
+QString stepToString(OperationStep);
+
 enum OperationType
 {
 	OperationNone,
diff --git a/code/ryzom/tools/client/ryzom_installer/src/stdpch.h b/code/ryzom/tools/client/ryzom_installer/src/stdpch.h
index 4ebe147f0..d066915d7 100644
--- a/code/ryzom/tools/client/ryzom_installer/src/stdpch.h
+++ b/code/ryzom/tools/client/ryzom_installer/src/stdpch.h
@@ -54,8 +54,10 @@
 
 #include <string>
 
-#include <nel/misc/types_nl.h>
-#include <nel/misc/config_file.h>
+#include "nel/misc/types_nl.h"
+#include "nel/misc/debug.h"
+#include "nel/misc/path.h"
+#include "nel/misc/system_info.h"
 
 #endif
 
diff --git a/code/ryzom/tools/client/ryzom_installer/src/utils.cpp b/code/ryzom/tools/client/ryzom_installer/src/utils.cpp
index 0a31629f9..25f084726 100644
--- a/code/ryzom/tools/client/ryzom_installer/src/utils.cpp
+++ b/code/ryzom/tools/client/ryzom_installer/src/utils.cpp
@@ -563,3 +563,51 @@ CCOMHelper::~CCOMHelper()
 	if (m_mustUninit) CoUninitialize();
 #endif
 }
+
+CLogHelper::CLogHelper(const QString &logPath)
+{
+	// disable nldebug messages in logs in Release
+#ifdef NL_RELEASE
+	NLMISC::DisableNLDebug = true;
+#endif
+
+	// don't create a file for the moment, we'll create it manually
+	NLMISC::createDebug(NULL, false);
+
+	// ryzom_installer.Log displayer
+	NLMISC::CFileDisplayer *LogDisplayer = new NLMISC::CFileDisplayer(qToUtf8(logPath) + "/ryzom_installer.log", true, "DEFAULT_FD");
+	NLMISC::DebugLog->addDisplayer(LogDisplayer);
+	NLMISC::InfoLog->addDisplayer(LogDisplayer);
+	NLMISC::WarningLog->addDisplayer(LogDisplayer);
+	NLMISC::ErrorLog->addDisplayer(LogDisplayer);
+	NLMISC::AssertLog->addDisplayer(LogDisplayer);
+
+	std::string type;
+
+#ifdef NL_RELEASE
+	type = "RELEASE";
+#else
+	type = "DEBUG";
+#endif
+
+	// Display installer version
+	nlinfo("RYZOM INSTALLER VERSION: %s (%s)", Q2C(QApplication::applicationVersion()), type.c_str());
+	nlinfo("Memory: %s/%s", NLMISC::bytesToHumanReadable(NLMISC::CSystemInfo::availablePhysicalMemory()).c_str(), NLMISC::bytesToHumanReadable(NLMISC::CSystemInfo::totalPhysicalMemory()).c_str());
+	nlinfo("OS: %s", NLMISC::CSystemInfo::getOS().c_str());
+	nlinfo("Processor: %s", NLMISC::CSystemInfo::getProc().c_str());
+}
+
+CLogHelper::~CLogHelper()
+{
+	NLMISC::IDisplayer *LogDisplayer = NLMISC::ErrorLog->getDisplayer("DEFAULT_FD");
+
+	if (LogDisplayer)
+	{
+		NLMISC::DebugLog->removeDisplayer(LogDisplayer);
+		NLMISC::InfoLog->removeDisplayer(LogDisplayer);
+		NLMISC::WarningLog->removeDisplayer(LogDisplayer);
+		NLMISC::ErrorLog->removeDisplayer(LogDisplayer);
+		NLMISC::AssertLog->removeDisplayer(LogDisplayer);
+		delete LogDisplayer;
+	}
+}
diff --git a/code/ryzom/tools/client/ryzom_installer/src/utils.h b/code/ryzom/tools/client/ryzom_installer/src/utils.h
index e3de8155b..980826a16 100644
--- a/code/ryzom/tools/client/ryzom_installer/src/utils.h
+++ b/code/ryzom/tools/client/ryzom_installer/src/utils.h
@@ -58,6 +58,8 @@ QString qFromWide(const wchar_t *str);
 // convert an QString to wchar_t*
 wchar_t* qToWide(const QString &str);
 
+#define Q2C(x) qToUtf8(x).c_str()
+
 // check if a shortcut already exists (the extension will be added)
 bool shortcutExists(const QString &shortcut);
 
@@ -92,4 +94,12 @@ public:
 	~CCOMHelper();
 };
 
+// a little helper class to init/uninit log
+class CLogHelper
+{
+public:
+	CLogHelper(const QString &logPath);
+	~CLogHelper();
+};
+
 #endif