Also had this problem when working on legacy project. My packege was CODESYS Code Generator ARM 4.0.3.0.package. To manage this I used PackageManagerCLI.exe. This tool does not validate certificates appearently. My command: "C:\Program Files\CODESYS 3.5.17.30\CODESYS\Common\PackageManagerCLI.exe" --profile="CODESYS V3.5 SP17 Patch 3" --install=""C:\Users\sample_user\AppData\Local\Temp\APInstaller\5wx1k02a.r2t\CODESYS Code Generator ARM 4.0.3.0.package""