I'm using Debian 7 with the latest ISPConfig. Everything works fine, but in the past few days i'm experiencing a strange FTP anomaly. I can log in to the previously created accounts and i can upload/overwrite files but i can't delete them. When i try to do that i get this error message: "550: Could not delete file.ext: Operation not permitted" I tried to create an FTP account manually (without the ISPConfig) and the result is the same. But the strangest thing is: It doesn't matter if i chmod the parent folder and the files to 777 the error message is still the same and i can't delete those files via Total Commander or FileZilla. I have to log in to SSH to delete them but it's not a solution because not everyone has root access. I did an "ls -la" and the permissions seems fine. I didn't touch the server or the configuration but i did an ISPConfig upgrade when i saw the new version. What is wrong here? Can you help me figure it out?