SOLVED Subdirectory in update folder suddenly missing or broken

[shawn_a]

enable debug mode and files should show owner of the files.

sounds like your host changed the files owner and your ftp user is either not in the same group of the file permissions need to be changed again to include group read, you will have to use your control panel or another ftp user with admin rights.

This can also happen if you set permissions to inclusive, some hosts have tools and configs that lock stuff down if they are given 755+