When you go on to open a Microsoft Office file, you may have noticed that it is opened in Protected View. When files are opened in Protected View, you can read them, with minimal risks to your Windows computer. If Microsoft Office detects a problem with the file you will see the following message:
Office has detected a problem with this file, To help protect your computer this file cannot be opened / Editing it may harm your computer
You may receive such messages if the files contain macros, data connections, ActiveX controls or even malware – and File Validation / Trust Center is detecting a problem with the file. It could be a malicious file or for a damaged file. You may receive even receive such messages, when you go on to open an embedded object, perform a mail merge or open a file from a viewer.
Office has detected a problem with this file
Files from the Internet and from other potentially unsafe locations may be malware. These agents may harm your computer. To help protect your computer, Microsoft Office opens files from such potentially unsafe locations in Protected View.
If you continue to receive such messages, you can change the default Trust Center settings to a less-safe macro security setting or even disable Protected View. But this is not recommended.
A better option would to move such files to a Trusted Location. You can add trusted locations, in any Microsoft Office document like Access, Excel, Visio, Word and PowerPoint
If you do this, Office files will not checked by Trust Center or opened in Protected View. But remember – you have to be very sure that the new location is completely secure.
Anand Khanse is the Admin of TheWindowsClub.com, a 10-year Microsoft MVP Awardee in Windows (2006-16) & a Windows Insider MVP since then. Please read the entire post & the comments first, create a System Restore Point before making any changes to your system & be careful about any 3rd-party offers while installing freeware.