Others might have access to your documents—the files are not as secure as you think.
Some of the settings that appear on the Security tab, including some that sound like security features, do not actually secure documents.
For example, Read-only recommended (available in Word and Excel) does not secure a document. It is only a guideline for readers—someone could still edit the document.
The Document Protection task pane and Protect Document features (available in Word) do not secure your documents against malicious interference either. They protect the format and content of your document when you collaborate with co–workers. These features are ideal when working on a document with a group of trusted colleagues.