If you are experiencing troubles after upgrading to 3491, it may be worth trying a fresh install, instead of an upgrade. Instructions for a fresh install can be found here > https://software.intel.com/en-us/xdk/faqs/general#uninstall-xdk <
The FAQ instructions include removing the entire application as well as all cached files and configuration files. We recommend that you keep the global-settings.xdk file if you want to preserve your list of projects (see the FAQ referenced above).
---- original post by James H. ----
I had found, one problem after another, after I had upgraded to 3491. I have completely uninstalled and reinstalled from scratch, before, so I had done the same thing this time and found that the XDK development environment works a LOT and I mean a LOT better. I am guessing that the upgrade to 3491 from a previous version, doesn't work as well as installing from scratch. I have read people's topics that seem similar to my own problems, so you might try this. When uninstalling I used a professional grade uninstaller that searched for those remnants that were left behind by the regular uninstaller. The project folders were left alone. Make a copy of your project folders and put them someplace safe, before you do this, just in case.