To improve security Microsoft Office prevents some previous versions of Microsoft Office file types should from being opened, without the help of Protected View in Trust Center.
File Block feature in Office
File Block prevents outdated file types from opening and can cause your file to open in Protected View. The code used to open and save these older formats have vulnerabilities that hackers can exploit. Thus, they present security risks that should be avoided, if possible. File Block settings are made by the system administrator if you work in an organization.
File Block helps with the following:
- Encourage similar Office file types that are used in your organization
- Lower security threats that target older Office file types
- Blocked file types that open in Protected View in Office by default
Examples of blocked, previous versions of Office programs are:
- Word 95 documents and templates
- Word 6.0 documents and templates
- Word 2.0, and earlier, documents and templates
- Excel 4.0 workbooks and spreadsheets
- Excel 3.0 and 2.0 spreadsheets
- Excel 4.0, 3.0, and 2.0 macro sheets and add-in files
Office Trust Center
You can of course, always configure your setting via the Trust Center.
For each file type, you can select the Open & save checkboxes. By selecting Open, the document blocks this file type or opens it in Protected View. By selecting Save, the document is prevented from being saved in this file type.
If you try to open or save a blocked file, you can receive an error message like: You are attempting to open or save a file that is blocked by your registry policy setting or File Block settings in the Trust Center.