Your advice on page IntelliSense Issues? | GameDev.tv
" In the extensions panel; select the C# extension, click on the cog icon, and then select ‘Extension Settings’. This will open up an new window and you want to scroll down the list until you find “Omnisharp: Use Global Mono”. Then, change the dropdown to “always” and click on Restart Omnisharp from the popup window."
In VSC C# plugin version 1.25.0, “Omnisharp: Use Global Mono”. no longer exists.
What should be done if it’s does not exists cause i am getting an error to download mono again and again but i have it installed already
To get omnisharp working (in my case), do these two: installed monodevelop from their site, https://www.monodevelop.com/. Then, on the VSC menu, open the omnisharp settings by clicking on: file, preference, settings and search for ‘Omnisharp: Use Global Mono’ and set it to ‘Always’. Then restarted VSC. Make sure VSC is using C# version 1.24.4. If not, click on the cog icon on the C# extension, click ‘install another version’, and select 1.2.4 – restart VSC.
This might become more of a problem when Unity drop mono and move completely to C# and .NET (native) in later editor versions.