In this page, you can adjust some preferences that affect performance of processing C++ code.
Index Unreal Engine source files
Clear this checkbox to skip indexing of the Unreal engine code. Normally you want to do this if you notice any performance degradation when developing your game.
When the indexing is enabled, you will have a number of features. For example, use any symbols from the engine and ReSharper will automatically add missing #includes, or find usages of engine classes — for example,
If the indexing is disabled, ReSharper will still index header file names, which is very fast but it will let you have code completion for includes, for example,
Index third party code
Clear this checkbox if you want to skip indexing source files under the ThirdParty folder of the engine.
Clear this checkbox if you want to skip indexing source files under the Plugins folder of the engine.
Enable background indexing of Unreal Engine source files
ReSharper indexes the engine code in the background by default, so that you can start working with your game logic code long before the engine code is fully processed. Turning off background indexing will result in a faster but more intrusive initial indexing.