Macbook Pro with Catalina doesnt go past user login screen

Macbksr wrote:

i had updated to Catalina, and every since OS doesnt go past the login screen, after password , apple logo is displayed along with horz bar and after sometime get a message that "some problem occured "and system restarts again

tried reinstalling OS from drive, internet and external drive, none of them solved the issue. also space on hard drive is very less, may be its an issue.. anyone had similar problem ?

i have personal files so didnt want to erase the disk

Boot into Recovery (Command R) and from the dropdown menu: Utilities>  Disk Utility> run the First Aid on your Macintosh HD (and the "Macintosh HD-Data" volume as well if Catalina) If errors are found and repaired, run again until no errors reported.

Recovery: https://support.apple.com/en-us/HT204904

Then reboot holding the Option Key and select your Macintosh HD to boot.

Can you boot into Safe Mode?

I hope that you will start regular system backups so you don't have to worry about your data in the future.