- Microsoft Excel will now disable blocked file types from workboglinks by default
- The files will either not update or display a #bloked error
- Other security updates are coming soon to excel, so be sure to update
External workboglink, which points to file types blocked by Excel’s Trust Center, will be disabled by default, starting in October 2025, as Microsoft tightens by reducing the potential security risks associated with indirect access to non-supported or high risk types in its spreadsheet software.
When the policy comes into play, workbooks with these types of links will either not update or display a # -blocked error.
Microsft confirmed that users would see a business bar banner warning in Build 2509, but new or refreshed links to blocked file types will be stopped from Build 2510 if the policy remains unconfigured by users or administrators.
Excel to disable external workboglink to blocked file types
When the change comes into force, any file type listed in the Trust Center’s file block settings is blocked when referring to through external links. “Inspection of the error will confirm that it is due to a limited file type,” Microsoft added to a support page.
Microsoft does not recommend that there are refreshing external links to blocked file types: “Disabling these protections reduces security and should only be done with caution.”
Users who are willing to take this risk can open the registry editor, click ‘Start’, click ‘Run’, Write ‘Regedit’ and then click ‘OK’. It is strongly recommended to carry out a backup of the registry before changes.
By deactivating them by default, Microsoft will close a road that is often used in phishing and other malware delivery that utilizes indirect access to risky file types.
A separate list in the Microsoft 365 road schedule entitled “New Trust Center -Settings to Block File Opening Using Uncertain Protocols” explains “New Settings in the Trust Center will allow users to limit or allow file that opens FTP/HTTP protocols and relapse to Frontpage refresh calls (FPRPC) -protocol.” This change is expected to roll out this month.
