If you have added a server to CFB, then you can see at the bottom right corner of the IDE that the CFCs are getting indexed. CFB uses the server settings to provide code assist for datasources, CFCs. This might take a lot of time since it indexes all the files in the webroot. This setting can be disabled in the preferences section. Navigate to Window -> Preferences -> ColdFusion -> Server Settings. Mac users can find Preferences under Adobe ColdFusion Builder (standalone) or under Eclipse (plugin installation).
CFB indexes all the CFCs located under webroot and mappings directory for the servers defined. By default these options are checked. One can uncheck 'Build server settings' and can observe that the build is not initiated when the CFB is started or when the server is started/added/refreshed.
If the webroot or mappings path contain a few files then I would recommend users to keep the default settings as it is since it would not take much time for the CFCs to get indexed.
ColdFusion Builder also provides an option of indexing files only in workspace and not the entire server webroot and mappings directory. This can be achieved by unchecking the options available under Server settings page (as explained in the previous section) and enabling 'Build CFCs in project on startup' under Preferences -> ColdFusion -> Startup. By default this is enabled.
If you are importing a very large project then I would recommend that you disable this option since it might take long time to index these project files. Once the project is imported successfully then enable this option and restart Builder. Indexing large project is always an expensive operation, however if one disables this then the code assist for the CFCs will not be shown.