Flex Builder suddenly stopped generating the swf of the modules in the output folder, the project properties is set to build automatically and all the modules are listed under Flex Modules in the project properties.

I didn't change any configuration, I was working on a project and modifying modules and the swf files in the output folder where getting updated until suddenly I noticed that any modifications in the modules where not reflected when I run the application so I checked the swf files of the modules in the output folder I found that they don't get regenerated when the module is modified. I tried restarting the flex builder but nothing changed.