Antivirus/EDR Interference: Your security software is actively flagging or blocking the execution of the MSI installer.

Insufficient Privileges: Your current Windows user account does not have the local administrative rights required to install system-level software.

File Corruption: The MSI file is damaged or incomplete due to a fragmented download or transfer error.

UAC Auto-Deny Mode: Windows User Account Control (UAC) is configured to automatically block elevation requests without a prompt.

SSL/TLS Handshake Failure: If the error occurs during a remote or scripted deployment, the endpoint computer may be blocking the HTTPS connection because it does not recognize the server's security certificate. Especially, if you are using a self-signed certificate.

Temporarily disable your antivirus software or add the Essential Exclusions and the Temporary Exclusions to the software’s exclusion/whitelist. Check out the Antivirus & EDR Configuration Guide for more information. Additionally, if your antivirus or EDR has a "Behavioral Shield" or "Sandbox" feature (such as Avast, AVG, or Comodo), it is often necessary to disable it temporarily during the installation in addition to adding these path exclusions.

Manually right-click the MSI file and select Run as administrator, or execute the installation from an elevated Command Prompt window.

Obtain a new copy of the installer from the System > Download Agent screen to address issues related to file corruptions.

Change the User Account Control settings to an interactive mode (do not use "Never Notify") to allow the system to prompt for the necessary installation credentials.

Correct the download link to use http:// instead of https:// to bypass TLS errors. If you are comfortable managing security certificates, you can manually add the Teramind server’s trusted certificate to the endpoint machine for Windows to trust the server. Note that the certificate must be installed into the endpoint's Trusted Root Certification Authorities store.