We recently upgraded from 6.5 to 7.1 (R6). Had a bunch of people with a Host Checker issue, either reporting that the HC install failed, or that the computer security was unsatisfactory. Couple of workarounds, firstly (potentially optional) ensure 'Check for publisher's certificate revocation' is unticked in IE Advanced Settings. Then get the user to go to Control Panel and remove 1. Juniper Networks Host Checker, 2. Juniper Networks, Inc. Setup Client. No need to get rid of all the components, and the good thing about this suggestion is the user does not need admin privileges, and no need to push the HC software out to everyone. Another thing that helped, in conjunction with the notes above, is to try the install through IE, instead of trying it through the older (e.g. 6.5) version of NetworkConnect. Worked for us, hope it works for you.
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