A read-only folder is a directory where the operating system or administrator has restricted file modification permissions. This prevents adding, changing, or deleting files within that folder by users lacking explicit write access. Attempting to save a file directly into such a folder typically results in an error message. It differs from a folder with write permissions solely granted to specific users or the system itself.

Common examples include critical system folders like "Program Files" on Windows or "/usr" on Linux, which protect core OS functions from accidental user changes. System administrators also configure shared network drives as read-only for specific user groups to ensure sensitive documents remain unchanged. Cloud storage platforms like Dropbox or OneDrive might temporarily set local folders as read-only during sync conflicts or maintenance.

The primary advantage of read-only folders is enhanced security and system stability by preventing unauthorized or accidental modifications to vital files. A key limitation is user frustration when needing to save relevant content; workarounds involve saving a copy to a writable location and then moving/copying it with appropriate permissions. Ethically, permissions should balance protection against excessive workflow disruption, potentially requiring users to request access changes from administrators.