When I update my custom developed component it throws the below error
Warning JInstaller: :Install: File already exists /path/controller.php Component Update: Failed to copy site files.
Initially I thought it was because of file permission issue but it doesn't look like that.
While debugging the core code I found the problem happens in copyFiles method under /libraries/cms/installer/installer.php where the overwrite flag is set to false.
What could be the problem? In my XML I have method='update' only.