My iMac Pro is taking very long time to verify password during login

It takes a very long time to select the account I want to log into and to verify the password after entering it. I started it in safe mode, but it still takes a long time to select the account and verify the password. Additionally, my Finder keeps crashing very frequently. I have almost 150 GB of free space on my disk, and I have no idea why this started happening all of a sudden.