How to Fix - ICS File - Microsoft has Identified a Potential Security Concern

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After a recent Microsoft Outlook update to protections for Microsoft Outlook Information Disclosure Vulnerability released on Dec 12, 2023, users have been seeing a new Microsoft Outlook Security Notice when opening ICS files.

This issue only effect's "Classic" Outlook as "New" Outlook does not currently support Importing ICS files.

Workaround for the Issue

Currently just selecting "Yes" will work around this issue and add the ICS to Outlook correctly. This warning is just a false positive from the bad Outlook Update.

If you want to get rid of this message, you can do the following to disable the Security Popup. Please note this stops all Security Notices, not just the false positive, so we do not recommend this. To disable the message:

1. Press the Windows Key + R to open the Run window.
2. In the Run window, type regedit, and then click OK.
3. Navivate to the following key (if the subkey does not exist, create it manually): HKEY_CURRENT_USER\Software\Microsoft\Office\xx.0\Common
  • Note - Replace "xx.0" with 12.0 for Office 2007, 14.0 for Office 2010, 15.0 for Office 2013, and 16.0 for Office 2016 and later.
4. Right Click the registry subkey, select New on the Edit menu, and then click Key.
5. Type Security, and then press Enter to name the key, then select it.
6. On the right, right click, select New, and then click DWORD Value.
7. Type DisableHyperlinkWarning, and then press Enter.
8. Right-click the new DisableHyperlinkWarning entry, and then click Modify.
9. In the Edit DWORD Value, click Decimal, and then type 1 to disable the warning.
10. Click Ok and close the Registry.

You can reenable the Warnings later by changing the value at step 9 to 0 instead of 1.