IntelliSense is not working in SQL Server Management Studio

Question

We use SQL Server Management Studio 2008 R2. IntelliSense works with SA account perfectly. But it is not working with Windows Authentication user. The user has access master db

Answer 1

Turning Query > SQLCMD Mode on and off again fixed the issue for me in SSMS 18.1, even though it was never enabled to begin with.

After trying all the answers here to no avail and giving up, I remained curious about the SQLCMD Mode mentioned in Chow Lover's answer. I turned it on to see what it did, but noticed no change so turned it off again. Intellisense suddenly awoke and has been working fine since.