Visual Studio error identifier is undefined

So, I have installed Visual Studio 17 for my Unreal Engine. I used Visual Studio 15 before. I know that Intellisense takes a lot of time to catch up with Unreal identifiers but I have waited for hours and Intellisense complains even with FName. It shows an error with a red squiggly line which says identifier “…”(<-could be FName,FString,AActor,etc) undefined.enter image description here I developed the project in VS 15 till now and now I upgraded to VS17 and then I wanted to finish the project in VS17. But now Intellisense is acting weird. Also VS17 can’t even open header files located inside a folder.The ones I had already opened in Visual Studio 15 work ok but complain of not being able to open source fileHeader files error. Compiling from the Unreal Engine still shows no error though. And the project runs fine. Attaching 2 pics below highlighting my issues.ALso VS17 also complains about being unable to open source file. I have tried reinstalling VS17 and even adding /YU for making Intellisense load faster but it still doesn’t help. Also, when I type in Unreal commands, it doesn’t even show up the commands or the information for them like their prototype and all the good stuff that Intellisense is supposed to help with.