Whenever you find the problem in Starting Zend Studio , and it is not giving any error then just do 3 simple steps Close ZDE. Locate the fileTypes directory under {your user home directory}\ZDE\config_X.Y\fileTypes and delete it.(Where X.Y are Zend Studio version numbers,for versions of Zend Studio older than 3.5.x this directory is named:{Your user home directory}\ZDE\config\fileTypes) Start ZDE again.