diff --git a/setup/backup.class.inc.php b/setup/backup.class.inc.php
index 1ec7c7ada..bbf0adfab 100644
--- a/setup/backup.class.inc.php
+++ b/setup/backup.class.inc.php
@@ -227,7 +227,7 @@ class DBBackup
 		{
 			$sFile = $sTmpFolder.'/config-itop.php';
 			$this->LogInfo("backup: adding resource '$sSourceConfigFile'");
-			copy($sSourceConfigFile, $sFile);
+			@copy($sSourceConfigFile, $sFile); // During unattended install config file may be absent
 			$aRet[] = $sFile;
 		}
 
@@ -248,30 +248,33 @@ class DBBackup
 			SetupUtils::copydir($sExtraDir, $sFile);
 			$aRet[] = $sFile;
 		}
-		$aExtraFiles = MetaModel::GetModuleSetting('itop-backup', 'extra_files', []);
-		foreach($aExtraFiles as $sExtraFileOrDir)
+		if (MetaModel::GetConfig() !== null) // During unattended install config file may be absent
 		{
-			if(!file_exists(APPROOT.'/'.$sExtraFileOrDir)) continue; // Ignore non-existing files
-
-			$sExtraFullPath = realpath(APPROOT.'/'.$sExtraFileOrDir);
-			if (strncmp(APPROOT, $sExtraFullPath, strlen(APPROOT)) !== 0)
+			$aExtraFiles = MetaModel::GetModuleSetting('itop-backup', 'extra_files', []);
+			foreach($aExtraFiles as $sExtraFileOrDir)
 			{
-				throw new Exception("Backup: Aborting, resource '$sExtraFileOrDir'. Considered as UNSAFE because not inside the iTop directory.");
-			}
-			if (is_dir($sExtraFullPath))
-			{
-				$sFile = $sTmpFolder.'/'.$sExtraFileOrDir;
-				$this->LogInfo("backup: adding directory '$sExtraFileOrDir'");
-				SetupUtils::copydir($sExtraFullPath, $sFile);
-				$aRet[] = $sFile;
-			}
-			elseif (file_exists($sExtraFullPath))
-			{
-				$sFile = $sTmpFolder.'/'.$sExtraFileOrDir;
-				$this->LogInfo("backup: adding file '$sExtraFileOrDir'");
-				@mkdir(dirname($sFile), 0755, true);
-				copy($sExtraFullPath, $sFile);
-				$aRet[] = $sFile;
+				if(!file_exists(APPROOT.'/'.$sExtraFileOrDir)) continue; // Ignore non-existing files
+	
+				$sExtraFullPath = realpath(APPROOT.'/'.$sExtraFileOrDir);
+				if (strncmp(APPROOT, $sExtraFullPath, strlen(APPROOT)) !== 0)
+				{
+					throw new Exception("Backup: Aborting, resource '$sExtraFileOrDir'. Considered as UNSAFE because not inside the iTop directory.");
+				}
+				if (is_dir($sExtraFullPath))
+				{
+					$sFile = $sTmpFolder.'/'.$sExtraFileOrDir;
+					$this->LogInfo("backup: adding directory '$sExtraFileOrDir'");
+					SetupUtils::copydir($sExtraFullPath, $sFile);
+					$aRet[] = $sFile;
+				}
+				elseif (file_exists($sExtraFullPath))
+				{
+					$sFile = $sTmpFolder.'/'.$sExtraFileOrDir;
+					$this->LogInfo("backup: adding file '$sExtraFileOrDir'");
+					@mkdir(dirname($sFile), 0755, true);
+					copy($sExtraFullPath, $sFile);
+					$aRet[] = $sFile;
+				}
 			}
 		}
 		if (!$bSkipSQLDumpForTesting)