If you try to upgrade your WordPress installation with the Automatic Update option and after 2 to 7 minutes you get this error:
Could not copy file.: /public_html/wp-admin/css/theme-editor.dev.css
Other sites advise to change the file permissions to 777 or 755, or to deactivate all the plugins, or to delete the upgrade directory in the wp-content. None of these solutions worked for me.
Solution: Change the FTP Server to ProFTPD
If you manage your server you have to change your FTP Server in the WHM, or if you are in a shared server you have to ask to your hosting company to change it (you need to be root for this):
Change the FTP Server from Pure-FTPD to ProFTPD
Once I did this the Automatic Update from WordPress run in 15 seconds, very fast with a successful update
Post author: Daniel Semper