SamCogan.com

After having to solve this problem a number of times I figured I ought to write this down. IIS7 by default will not show detailed PHP error messages, just a friendly 500 error, not much use when debugging. So to enable detailed errors you need to run the following from the command line:

%windir%\system32\inetsrv\appcmd.exe set config -Section:system.webServer/httpErrors -errorMode:Detailed

Then resset IIS with IISReset