Microsoft Office Security Warning for ICS Files in Outlook

Hi, in this post, let’s discuss the Microsoft Office Security Warning for ICS Files in Outlook. Everyone knows about Outlook, and we all work on this application. Outlook is one of the most important email management applications introduced by Microsoft.

It is famous for email management and provides many features, such as comprehensive contact management and time-scheduled applications. This is the best way for users to reduce their daily work. After installing the Outlook Desktop Security updates on December 12, 2023, users get a warning note when they attempt to open an.ICS file.

ICS files are also known as iCalender files. They are universal calendars used by many email programs, mainly Outlook. The primary purpose of this calendar is to allow the user to send calendar meetings, events, and appointments in different calendar programs.

In this post, we can discuss how Outlook users have been experiencing unexpected security warnings when attempting to open.ICS files and Workaround for this issue.

The issue primarily affects users of the “Classic” Outlook, as the New Outlook does not currently support importing.ICS files. What is the issue? First, we can discuss that, as I mentioned, some users experience Warning messages when they try to open an ICS file.

The Security notice warns users that with a message ‘‘Microsoft Office has identified a potential security concern”
You may get 2 choices for this warning Yes or No to Continue

Numbers	Warning Message
1	”Microsoft Office has identified a potential security concern.” This location may be unsafe.” (”Hyperlinks can be harmful to your computer and data. To protect your computer, click any of those hyperlinks from trusted sources.” )

Microsoft Office Security Warning for ICS Files in Outlook – Table 1

Microsoft Office Security Warning for ICS Files in Outlook - Fig.2 Creds to MS — Microsoft Office Security Warning for ICS Files in Outlook – Fig.2 Creds to MS

The issue occurred after the installation of security updates to address the Microsoft Outlook Information Disclosure Vulnerability (CVE-2023-35636). It primarily affects Classic Outlook users.

Microsoft Office Security Warning for ICS Files in Outlook - Fig.3 Creds to MS — Microsoft Office Security Warning for ICS Files in Outlook – Fig.3 Creds to MS

What is the Workaround for this Issue?

Microsoft found a temporary workaround for this issue when the Outlook Team discovered problems with the update during tests. Recently, they turned off the update and are working on fixing it. So there is a temporary solution for this as ” users can use a registry key workaround”

The users can temporarily disable the security notice by using the Registry key
Open the Run (Win+R)
Type regedit
Click OK

Workaround	Info
Group Policy registry path	HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\common\security
OCT registry path	Computer\HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Security

Microsoft Office Security Warning for ICS Files in Outlook – Table 2

Note: When you try to disable the Security Notice, for.ICS files will stop all the security Notice prompts for all types of files.

Microsoft Office Security Warning for ICS Files in Outlook - Fig.4 — Microsoft Office Security Warning for ICS Files in Outlook – Fig.4

After opening the Registry, you have to enter the appropriate path. The path below you have to enter in the registry.

Computer\HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Security

Microsoft Office Security Warning for ICS Files in Outlook - Fig.5 — Microsoft Office Security Warning for ICS Files in Outlook – Fig.5

After entering the path right, right-click on the security key, select the New option, and select the DWORD(32-BIT) value.

Microsoft Office Security Warning for ICS Files in Outlook - Fig.6 — Microsoft Office Security Warning for ICS Files in Outlook – Fig.6

You have now created a new key value, which you should name DisableHyperlinkWarning. Then, double-click on the New value (DisableHyperlinkWarning). You must enter the value to stop security notice prompts.

Value data as 1 to Disable
Value data as 0 to Enable
Click on the Ok

Microsoft Office Security Warning for ICS Files in Outlook - Fig.7 — Microsoft Office Security Warning for ICS Files in Outlook – Fig.7

Reference

Outlook prompts security notice opening.ICS files after installing protections for Microsoft Outlook Information Disclosure Vulnerability released: Dec 12, 2023

We are on WhatsApp. To get the latest step-by-step guides and news updates, Join our Channel. Click here –HTMD WhatsApp.

Author

Krishna. R is a computer enthusiast. She loves writing about Windows 11 and Intune-related technologies and sharing her knowledge, quick tips, and tricks about Windows 11 or 10 with the community.

Microsoft Office Security Warning for ICS Files in Outlook

Sign up to get the best of How To Manage Devices straight to your inbox!