Since the April 2026 security update was released, Remote desktop connections have now started displaying a new warning whenever an RDP file is opened.

With this specific warning it will not let you save the access in the tick boxes which can be annoying for users who access multiple RDP sessions. This warning means that the RDP file has not been digitally signed which means it doesn’t know who has made it and where it has come from.

To sign the RDP file, it requires a certificate to be placed in the trusted root folder on the local computer if the RDP connects to a terminal server the certificate would need to be created on it and applied to the local machine. The trusted root is the directory which your operating system treats as inherently trustworthy.

However, if it is connecting to another computer or more personal uses, you can self-sign an icon by creating a certificate locally. Once the RDP file has been signed it will allow you to save the access to resources on the local computer and will give a slightly different warning and will say who the publisher of the file is.

The reason Microsoft introduced these protections was due to threat actors distributing malicious RDP files that silently redirected victims’ sessions and exposed local drives, clipboard data and authentication tokens.