Thank you for contacting us.
I just reviewed the error reports you sent us and it seems that you are not able to download the files necessary for installation, i.e. the files downloaded doesn't match the expected hash code. This is the reason for getting the 'Connectivity problem' dialog.
Is it possible that you have any network restriction or firewall policy that forbids the download of MSI files? Could you, please, give it a try on another machine?
Still, if the problem persists, you can download the MSI installer of JustDecompile from here
Let me know if you need any further assistance.
the Telerik team
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