Windows 2003 and Windows XP do not accept EXEs which are SHA256 code signed and Microsoft broke support for SHA1 code signed certificates with its KB2870699 security patch (see  As a result, when running our installer on Windows XP and Windows 2003 after downloading you may see this:


Security Warning Dialog

Microsoft gives the following solution to this problem:
To resolve this you can update to SP3 on Windows XP and for Windows 2003 you can apply Microsoft’s patch KB938397, but the easiest solution is to open Internet Options within Internet Explorer and click on Advanced tab and enable “Allow software to run or install even if the signature is invalid” as follows:


IE Security Options

Additional information about Microsoft’s support of SHA1, SHA2 and SHA256 can be found at: