Intellisense in IntelliJ no longer working

Autocomplete Problem Overview

I'm currently running IntelliJ IDEA 13.1. While running IntelliJ 13 intellisense/autocomplete stopped working. I tried upgrading and it still doesn't work.

I can explicitly invoke code completion using ctrl+space. I looked in Settings->Editor->Code Completion and nothing looks out of place. Is there somewhere else that turns this feature on/off?

Autocomplete Solutions

Solution 1 - Autocomplete

For me it was because I did not have a folder marked as Source Root (it appears in blue).

To fix, right click your root source directory -> Mark As -> Source Root.

Solution 2 - Autocomplete

Check to see if you accidentally turned on Power Save (File/Power Save Mode) I myself just discovered that File/Power Save Mode does turn it off. I was having the same problem and must have accidentally set Power Save Mode to on.

Solution 3 - Autocomplete

File -> Settings-> Editor-> General -> Code Completion-> Auto pop up code Completion

Solution 4 - Autocomplete

If other options mentioned is already true for you,try Setting up Sources/Test folder as Sources Root/Test Sources root as it did the trick for me. I had forgot it.

Right click on folder, choose "Mark Directory as" Test Sources or Sources Root, or whatever applicable. :)

Solution 5 - Autocomplete

Had the same problem and none of these helped. What I realized was that on mac, control + space is used by the OS to change language inputs and it overrides intellij. So if you are on mac having multiple input languages on your keyboard, consider changing the shortcut for it :)

Solution 6 - Autocomplete

I'm using Mac and when I upgraded to Big Sur my intellisense stopped working.

This is due Big Sur has a shortcut for Input Source. By disabling Mac shortcut, will make Intellisense work again.

You can see the option to disable in mac:

Solution 7 - Autocomplete

I tried all the above option and it did not solve the issue. In my case:

THE ISSUE: node_modules was not loaded in the file structure of the project.

THE SOLUTION: go to explorer(finder/nautilus) find the .idea folder in the project and delete it. Then re-import the project. Once I re imported the project it loaded the node_modules folder as library root

Note: It will take a few seconds for IntelliJ to index all the libraries. You will see a loader on the bottom right next to line number info.

Solution 8 - Autocomplete

Try disabling all plugins you have. I installed Codota and it turns out to be garbage. I uninstalled it and disabled the plugin in IntelliJ and it worked

Solution 9 - Autocomplete

For me, it was I hadn't yet set up the JDK.

Type something out, Ctrl+Space to try to autocomplete. If it fails, do Alt+Space and if the option comes up to setup JDK, do that.

Solution 10 - Autocomplete

In my case, I restarted the Intellij and everything came back to normal.

Solution 11 - Autocomplete

Had the same problem until:

Third party JDK installed
Configured in module settings: right click on project name, then "Open module settings" -> SDKs -> "+". Pick the jdk root folder and Idea will take care of the rest.
Re-indexed a bunch of things. It happens automatically, just be patient

Solution 12 - Autocomplete

In IntelliJ 2017-2 to configure Autocompletion:

Settings -> Editor -> General -> Code Completion

Solution 13 - Autocomplete

In case this helps anyone; for me it was a windowing glitch of some kind. The suggestions popup showed on the wrong monitor, which I didn't notice the first time it happened.. after a while I saw what was happening. Resizing the window seemed to fix it.

Solution 14 - Autocomplete

If you're too lazy to restart your machine to fix the issue, you can kill the process taskkill /F /PID pid_number_of_idea64.exe (task manager -- view>select columns>PID) and then open CMD, head over to C:\Program Files\JetBrains\IntelliJ IDEA xxxx.xx.xx\bin, start idea.bat. Let this CMD window open. Please note that even after executing taskkill, idea64.exe process doesn't disappear from task manager. Try executing the same command again and you'd know that process doesn't exist anymore.

Solution 15 - Autocomplete

For me the code completion suddenly stopped working because I had nudged the IDEA window slightly off-screen, maybe just a pixel or two, which caused the code completion pop-up to (presumably) appear off-screen. Making sure the application window was fully visible fixed the problem.

Solution 16 - Autocomplete

> IMPORTANT >

If you had your email logged-in on IntelliJ Idea for a while and its token expire the Intellij will suddenly stop working or crash(My Version 2020.1.1).

Do two things.

1. file > sync settings with JetBrains account (log in here)
enter code here.
2. file > Invalidate cache / restart

Solution 17 - Autocomplete

In case none of these work for you, if you are using IdeaVim, make sure your ~/.ideavimrc does not override Ctrl+Space, you can check this in vim:

:verbose map <c-space>

In my case, it was set by ~/.vim_runtime:

Last set from ~/.vim_runtime/vimrcs/basic.vim line 208

Thanks @s1n7ax for the tip!

Content Type	Original Author	Original Content on Stackoverflow
Question	earthling	View Question on Stackoverflow
Solution 1 - Autocomplete	Loaf	View Answer on Stackoverflow
Solution 2 - Autocomplete	CrystalVisions	View Answer on Stackoverflow
Solution 3 - Autocomplete	Sergii Lisnychyi	View Answer on Stackoverflow
Solution 4 - Autocomplete	Anand Varkey Philips	View Answer on Stackoverflow
Solution 5 - Autocomplete	Javier Mendonça	View Answer on Stackoverflow
Solution 6 - Autocomplete	Federico Piazza	View Answer on Stackoverflow
Solution 7 - Autocomplete	T04435	View Answer on Stackoverflow
Solution 8 - Autocomplete	mdeligt_	View Answer on Stackoverflow
Solution 9 - Autocomplete	bob zhang	View Answer on Stackoverflow
Solution 10 - Autocomplete	codemonkey	View Answer on Stackoverflow
Solution 11 - Autocomplete	vizmi	View Answer on Stackoverflow
Solution 12 - Autocomplete	chrips	View Answer on Stackoverflow
Solution 13 - Autocomplete	Jochem Kuijpers	View Answer on Stackoverflow
Solution 14 - Autocomplete	Vijay Nandwana	View Answer on Stackoverflow
Solution 15 - Autocomplete	jpartanen	View Answer on Stackoverflow
Solution 16 - Autocomplete	Sami Haroon	View Answer on Stackoverflow
Solution 17 - Autocomplete	ifnotak	View Answer on Stackoverflow