Nautilus does not launch in Ubuntu 19.04

In my 18.04 setup I had problems with tracker causing the same issue, nautilus not launching, then it worked by killing tracker, but now that did not work either.

What did work, was resetting tracker. I performed a hard reset, you might try a soft reset, maybe it could work too, I didn't test, since it got fixed by the hard reset. Sidenote: I disabled search in files.

tracker hard reset in terminal :

tracker reset -r

tracker soft reset :

tracker reset -e

I also had this problem. All was good in the beginning, but after some time I was unable to open Files to access to my folders.

Try cleaning your operating system with Bleachbi:

sudo apt update
sudo apt install bleachbit 

Run Bleachbit and clean your OS, then restart the computer.

This worked for me.