‘Invalid digital signature’ error when installing CT 3.6 package

The following error may occur when installing the CT 3.6 package.

Failed to install a required file because ~~~.cab cabinet file has an invalid digital signature.
~~~ The certificate in the signature could not be verified.

Here are some possible causes of the error.

1. If the package file is damaged
2. If the root certificate related to the digital signature is not installed on the computer you are installing
3. If there is no root certificate of GlobalSign used in the CT package because it is a work PC in an environment where access to an external Internet network is impossible due to network separation
   

*In the window, you can enter certlm.msc to verify that the required root certificate exists in the list of root certificates installed on the computer

To solve the problem, you can try the following 3 methods.

1. Re-download the package file.
2. Manually install the root certificate of the digital signature used by the package.
3. Download the CT related root certificate from support.globalsign.com and reinstall the package.