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From Visual Studio, select “Tools” > “Options“.
Select “Text Editor” in the left pane.
Select the language you are using (C#, C++, Basic, etc.).
For C# and Basic, choose “IntelliSense“. For C or C++, choose “Advanced“, then scroll to the “IntelliSense” section.
For C# and Basic, check the “Show completion list after a character is typed” to disable it. For C/C++, you will have a few options, such as “Disable Auto Updating“, “Disable Squiggles“, and “Disable #include “Auto Complete“. Set any of these to “True” to turn them off.