UPDATE: Quicker solution by the user Hong given below:
Delete the caches folder: C:\Users\my_user_name\.AndroidStudio3.3\system\caches
=====================
Here’s what worked for me.
- Close Android Studio
- Go to C:\Users*your username*
- Locate the Android Studio settings directory named .AndroidStudioX.X (X.X being the version)
- Rename it to something like old.AndroidStudioX.X
- Start Android Studio, and when it asks if you want to import settings, choose the old directory
This should fix the issue.