Microsoft Office comes with a security feature called the Protected View feature. Trust Center contains security & privacy settings, which help keep your computer secure & safe. This feature ensures that files downloaded or directly opened do not deliver any malware or steal data.
Microsoft Office Trust Center

Files from the Internet and from other potentially unsafe locations can contain viruses, worms, or other kinds of malware, which can harm your computer.
Protected View in Office
To help protect your computer, files from these potentially unsafe locations are opened in Protected View.
By using Protected View, you can read a file and inspect its contents while reducing the risks that can occur.

The messages you see could be:
- This file originated from an Internet location and might be unsafe
- This file originated as an e-mail attachment and might be unsafe
- This file was opened from a potentially unsafe location
- This file was opened in protected View
- The Office has detected a problem with this file. Editing it may harm your computer
- Editing this file type is not allowed due to your policy settings
- Editing this file is not recommended due to your File Block settings.
When you see the Protected View Message Bar, decide how you want to proceed. This should depend on the color and the type of message you receive.
- If you know the file is from a reliable source, click Enable Editing.
- If you are unsure, Protected View lets you look over the file while turning off some functions like edit or print, which can trigger a virus to run. This allows you to read the file without potentially damaging your computer or network.
Trust Center
As mentioned, Trust Center contains security & privacy settings, which help keep your computer secure & safe. Go here to learn how to configure Trust Center. If you wish to disable Protected View, you can do so from the Trust Center.
The file was opened from someone else’s OneDrive storage
When you open a document on OneDrive which you don’t own, then you will receive this message. The full message goes as Be careful – This file is from someone else’s OneDrive. Unless you trust this person and want to continue collaborating with them, it is safer to stay in Protected View. It protects your PC from, documents that you don’t own and is shared with you online. Once you click on the Trust Documents From This Person option, the warning will be removed.
How to fix File validation failure?
When you see a message in Protected View that says “Office has detected a problem with this file. Editing it may harm your computer. Click for more details, then it’s because there is a security issue which will result in problems. So it’s best to get another co[py and from a trusted source.
