Apparently DoubleEscaping means ”+” go figure!
%windir%system32inetsrvappcmd set config “Web Site” -section:system.webServer/security/requestfiltering -allowDoubleEscaping:true
On an IIS7 server your URL cannot have a plus sign in it otherwise you”ll get a 404 error. Unless you get the detailed custom error you”ll spend pleanty of time wondering why although the page is there the web site dosen”t pick it up.
It does however with a plus in the file name (or the URL for that matter) then you”ll get the error, either recode so the plus sign is not used or use the code above to allow plus signs. We did the above whilst the developers recoded and then changed the true to false in the statement.