I am using the following code to try and create a file in the user's temp folder, but it will not. var fs = require('fs'); var os = require('os'); var ostemp = os.tmpdir(); var exec = require('child_process').exec; var file = fs.createWriteStream(ostemp + '\setup.exe'); ostemp will return a path similar to 'c:\users\user\appdata\local\temp' But the code above will save the file to local, and the filename will be tempsetup.exe Why is that?