Where is gone Audio preview?

I upgrade my project to 2019.3.7 newest, but all my previous BGM, sound files does not have audio preview at Inspector. And its file size just says 0.

Why and how to fix this?

I even tried drag and drop new sound file to this project, but same, no preview, can't use, hear.

 

Try right-click on the audio and reimport.

Also make sure the audio file is valid in something else, like an MP3 player.

Also, the inspector bottom area can get "crushed down" to nothingness, so look if there's a handle to lift it up.

See how I crushed this one down:

 

mp3 files does not have problems, it runs well at music player at window10.

Reimport, unity console says error.

--------
Errors during import of AudioClip Assets/Resources/Sound/Music/Adventure.wav:
FSBTool ERROR: An operating system based file error was encountered.
--------

And not crushed down at all. There is nothing below.

 

Google that FSB error... there's quite a few hits, but I don't know if they apply in your case. It's something though.

 

solved. Bitdefender's file protection was cause. When I stop it, and reimport all, things become normal.