Visual Studio Intellisense SLOW (VS2019 / UE4.25.1)


I have noticed that Intellisense takes AGES to update and start suggesting any auto-complete.
Adding/removing a single variable in header or switching to a different class would often take 10+ seconds to update Intellisense. I hope it does not come out as some sort of whining, but it heavily impacts my workflow when I want to make fast changes to the code.

My two questions are:

  1. Is anyone facing slow Intellisense to the point of finding it difficult to rely on it?
  2. Are there any solutions (aside from using Visual Assist) that could speed it up?

I’ve also seen some people downgrading to VS 2017 / earlier UE version (like 4.21), but this just sounds ridiculous (even though it may work).

P.S. One of the most common issues recently is that when creating a new project and adding classes, we get 13k+ or so errors from Intellisense. This is usually resolved by refreshing the project via File > Refresh Visual Studio Project in the main window. I wonder if things are somehow related.

P.S.S. Additionally header auto-complete doesn’t work well, so to fix it (kind of) one would go to Project Properties > NMake > Include Search Path and input a long string of paths. I wonder if this is also somehow related to an underlying problem that would be affecting Intellisense.

Hi, I have exactly the same problem and the same questions. It would be great if someone had this information.

Sometimes a plugin can heavily downgrade the speed: ReSharper, Visual Assist, TabNine, etc.
If you disable Intellise VS is still slow?
Is there any running process in the background?
Try to remove .vs, Binaries, Intermediate, Saved directories and .sln file then rebuild your project.
I think this isn’t related to UE according to these threads:

(My advice instead of VS: Rider. :wink: )

i have the same problem and I think two sides of the problem ;
when adding a class from intellsense does not list some folders like GameFramework or so…

there are 2 workarounds one is the one you did with NMake Intellisense which I did same too and you can also write
#include then it auto completes super fast …then change the <> to " " as it should be…

I believe this can be handles by Unreal by adding project file setting so when it generates it automatically load required folders.

The other problem is when you peek thru for example ActorComponent.h then more deeper it goes into Physics header files where it list bunch of header files from Physix but they are not in the same folder with the header file. The engine works because problem its include settings have those folders in the Engine project setting but you go thru the Game it can find the header file because their include statements are written in short form rather writing down the whole path…

Long story short most of those problems can be avoider if the Intellisense Include directories section include a macro that specifics all the underlying source file because it will hard for them to rewrite the engine header files…too many

So again most of these issues can be handled by Unreal …any slowness after will be acceptable…I believe most programs suffer from that. Intellisense does too much work therefore better to give a little heads up will solve all those problems, I believe

I try to report and explain in detail so maybe someone from Unreal sees and try to reproduce because if they are working on builds from the source those problems won’t happen probably.

Sorry for long reply. I did try removing the directories and rebuilding, but it didn’t work. I use vanilla VS with a few extensions (Toggle Comment, Test Adapter for Google Test and Boost.Test, ML.NET Model Builder (Preview), Live Share, VIsual Studio IntelliCode). I tried disabling them all but to no avail.

Disabling Intellisense fixes the speed, but of course that defeats the purpose because I wish to have the benefits it brings. In the end of the day I tried Visual Assist and for the best part it works well, but I think there were some things that I preferred in IntelliSense.

A different IDE is definitely something worth considering, thanks for the suggestion!

Im on VS2017 and I have the same problem. Intellisense is super slow, often its faster for me to reach the function than him. It even fails at searching functions which are like 10 lines of distance from the current cursor position. Also the behaviour is not consistent, sometimes its fast, others is slow. Too often I have to wait 20-30 seconds to get an answer from Intellisense, it is really really slowing down my work.

I like the minimal UI of VSCode and I’ve been using it with Unreal for a while now but today I gave Jetbrains Rider for UE a try and I was just stunned by how freaking fast the intellisense is and it has some pcool tools dedicated for UE development it’s still in preview not sure which version so you can get a license for the preview. I really hope I can save up for a full license when it’s fully launched. However from my experience it takes a lot of memory I guess ~

I am also using Rider, and recommend it as prediction works almost immediately