Edit: After half day, my wife’s Mac started having the same problem. I have then applied the solution that I found in the Apple
How To get The Finder Autocomplete Folder Names
Imagine the pain of typing the entire name of nested folders and subfolders in the Finder only to find that the folders path you typed doesn’t exist. Not only the entire process of typing out the path seems tough but is prone to mistakes as well. Fortunately Finder comes with a smart autocomplete feature that cuts down the typing to just the few unique letters of the folder name.
For trying autocomplete feature, launch the Finder dialogue (Finder’s Go>>Go To ) and type the first few letters of the folder’s path. Now press tab and Finder will autocomplete the folders name. For example typing /e and pressing tab will fill /etc/. This offcourse will work only when you don’t have other folders beginning with ‘E’ in the root folder.
This trick works even for hidden folders. Simply type the folder name and the folder will show up in the Finder. The alternative approach of toggling hidden files is quite cumbersome and time consuming. This trick works great when you want to see just few hidden files intermittently. The only factor to consider is to type a unique combination of letters to help Finder identify the folder.