Thanks it turned out the problem was that the directory that the Temporary Internet files were stored in no longer existed after the update to Windows 10. Trying to change this under the Control Panel application for Internet settings failed to change the directory as the one that it was trying to move the files from did not exist. The only way to correct the problem was to manually edit the registry key as explained here: https://msdn.microsoft.com/en-us/library/ms940828(v=winembedded.5).aspx

I use Expat to read XML files. See http://www.libexpat.org/. I use to this to read Excel XLSX files once they are unzipped with the zlib library.

My app was running fine with Windows 7 & 8.1 using URLDownloadTofile(NULL,sUrl,SFile,0,NULL). With the upgrade to Windows 10 it has stopped working. I've made sure my app has security settings to allow it through the firewall (and this hasn't changed) but now the request to download fails. Also the Visual Studio 2008 Document explorer now just comes up with "Unable to download " which makes me suspect it's a more general problem that just my app. I can't find any security settings that should be blocking my app. If any one could shed some light on my problem I'd be grateful. I've trawled around the web for a day with no useful results. Thanks, David.

R is great if you want to learn a programming language and is free, but if you want a powerful menu driven Stats tool, then you could try our program GenStat (www.genstat.com). It's much cheaper than SAS or SPSS and has more modern statistics. The software was started in 1968 so it has a long history of refinement and improvement.

David Baird VSN NZ Ltd GenStat developer.