File Block Settings In The Trust Center !link! (500+ BEST)
Imagine you roll out Office 365 and decide to block saving to .xls . A user opens a modern .xlsx file, makes edits, and hits Save As. They accidentally choose "Excel 97-2003 Workbook" from the dropdown. Office will immediately reject the action with: "Your administrator has blocked this file type from being saved."
You can deploy specific GUIDs for each file type. For example, the policy setting for blocking legacy Excel 2.0 spreadsheets is a simple registry key under: HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\16.0\Excel\Security\FileBlock file block settings in the trust center
If you use Group Policy, always set the "Set Default File Block Behavior" policy. This determines whether the user sees an error message, a warning, or a silent failure. The worst thing you can do is block a file type without a clear error message—your helpdesk will drown in "corrupted file" tickets. The "Open Anyway" Loophole (And Why You Should Close It) By default, when a file is blocked by these settings, the user gets a message and no option to override . However, older versions of Office (2010/2013) had a checkbox: "Do not show this message again and allow me to open." Imagine you roll out Office 365 and decide
| File Type | Extension | Risk Level | Recommended Action | | :--- | :--- | :--- | :--- | | | .xlm | Critical | Hard Block (Open & Save) | | Word 2 / Word 6.0 | .doc (pre-97) | High | Hard Block | | Excel 95 Workbooks | .xls (pre-97) | High | Hard Block | | PowerPoint 95 | .ppt (pre-97) | Medium | Protected View | | Web Pages | .htm , .html | Medium | Block Open (they trigger scripts) | Group Policy: Managing at Scale The worst way to manage File Block Settings is by walking to each desk. The best way is via Group Policy Administrative Templates (ADMX/ADML). Office will immediately reject the action with: "Your
The actual error depends on the Office version, but the fix is always the same: The IT admin must either unblock that file type globally, or the user must use a third-party tool to convert the file to a modern format. Look closely at the File Block Settings dialog. For each file type, there is a third option nested in the dropdown: "Open selected file types in Protected View" (instead of blocking them outright).
