I've just checked and a line in library/httpmodules/urlrewrite/urlrewritemodule.vb was changed after the release of 4.8.4, I suspect that may be your issue, you may want to try making the update yourself and recompiling to see if that resolves it for you. The line in question looked like this in 4.8.4

                    If sendTo.ToLower.IndexOf("?" & strParameterName.ToLower) = -1 And sendTo.ToLower.IndexOf("&" & strParameterName.ToLower) = -1 Then
               

but has been altered to read

     If sendTo.ToLower.IndexOf("?" & strParameterName.ToLower & "=") = -1 And sendTo.ToLower.IndexOf("&" & strParameterName.ToLower & "=") = -1 Then

Cathal and Sebastian, once again thanks for all your help. I have done a bit more testing, downloaded 4.8.3 and this issue does not happen so it looks like it was introduced in 4.8.4. However, I downloaded the 4.8.4 source files and changed the two lines of code in UrlRewriteModule.vb (at http://support.dotnetnuke.com/issue/ViewIssue.aspx?ID=7785&PROJID=2) back as suggested and recompiled but this did not fix the issue. Is it possible that maybe something else that was changed for the security fixes in 4.8.4 is causing this issue (see http://support.dotnetnuke.com/project/ChangeLog.aspx?PROJID=2)?

Thanks

Hi ESV, no, not yet, I would be glad if you could do it.