External hard drive too full to open!

My external hard drive is too full to open (checked on disk utility)

It is not visible in Finder but is visible on Disk Utility

500.08GB used, 0KB purgeable, 0KB free

Format: Mac OS Extended (Journaled)

I cannot mount the drive either, it doesn't work when I click it.

I've tried SMC reset, doesn't work either.

I have 2 MacBooks, and Air and a Pro and it is same for both macs.

What should I do? I don't want to format and erase my data...