Problem with using "sudo shutdown +TIME" command

My computer tries to shutdown but sometimes i get this error:

And so my laptop doesnt actually shutdown fully, it stops at the blackscreen above for endless hours, until I manually power it off with the power button.

So what do the error messages mean?
I suppose its got something to do with having USB drives plugged in?

Also recently about 10% of the time, when I eject or unmount a USB drive, it glitches and acts weird. It seems there is a malignant process causing the connection to the USB to hang and make my computer think the USB still needs to be connected or mounted. And also maybe it doesnt want to shutoff because of this too?

Is it maybe nemo's file indexer updating it's index of the USB drive?
How do I terminate all nemo related processed when i do the delayed shutdown command?