While these patches are often effective, they should be treated with caution. Always ensure you download such tools from reputable sources and verify their integrity before running them, especially in a production environment.

Select when prompted for the Store Location (this ensures all users, including the installer, can use it). Select Place all certificates in the following store .

: The most direct fix is to connect the machine to the internet and run Windows Update to automatically refresh the local Trusted Root Certification Authorities store.

Choose one of the methods below based on your infrastructure constraints and security policies to fix the error.

Before tearing your hair out, it's worth mentioning a related issue that can mirror the symptoms of a certificate error. The installer's ability to check for Windows Updates (for solution #1) or to validate online Certificate Revocation Lists (CRLs) can be blocked by an overzealous firewall. While the primary error message points to root certificates, ensure your network and local firewall rules allow standard HTTPS traffic (port 443), which is required for these verification processes.

Move the .CER file(s) to the offline machine using authorized media storage.

Navigate to the folder containing your Kepware installer executable.

The official recommendation from PTC, as stated in the error message itself, is to run Windows Update. This is the safest and most effective method for most users. The installer cannot find the required root certificates. Please apply windows updates.