Sometimes after installing many packages on a development installation of SugarCrm the Module Loader will take a long time to load. To regain the freshly installed SugarCrm speed of ModuleLoader you need to clean out the temp installation files (they will still be installed). You can use the commands below to clean it up to make it more responsive again. (This is working on 5.1.0b of SugarCrm, newer versions might behave differently).
Please note that you do lose the list of installed packages.
rm -f /<SUGARCRM_INSTALL_DIR>/cache/upload/*.zip rm -fr /<SUGARCRM_INSTALL_DIR>/cache/upload/upgrades/module/* rm -fr /<SUGARCRM_INSTALL_DIR>/cache/upload/upgrades/temp/* # truncate table upgrade_history in instance database