The grub bootloader crashes. How to find the reason?

Question

GRUB

Good evening.
There is ubuntu 16.04 and windows (installed by the second system).
The grub bootloader crashed twice in the last three days.
The glitch occurs by itself, not as a result of any actions.
For the first time, for no apparent reason, all the windows were minimized, the image on the monitor began to blink.
The second time, that is, literally an hour ago, google chrome closed, the top panel disappeared, the hot keys did not work (I tried to start the terminal, reboot the system).
When you reboot, the option to select the system disappeared. In bios, in the choice of boot priority, the "ubuntu" item disappeared altogether, only "windows".
Only reinstalling grub helps.
Marked the time (16:25) when the bootloader crashed for the last time. Opened /var/log/syslog. There are no appointments for this time.
Here is a piece of the log, records jump from 16:17 to 16:50

syslog

Dec 16 16:04:50 slonik-MS-7971 smartd[924]: Device: /dev/sdb [SAT], SMART Prefailure Attribute: 1 Raw_Read_Error_Rate changed from 117 to 118
Dec 16 16:09:01 slonik-MS-7971 CRON[14901]: (root) CMD (  [ -x /usr/lib/php/sessionclean ] && /usr/lib/php/sessionclean)
Dec 16 16:17:01 slonik-MS-7971 CRON[15193]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
Dec 16 16:55:50 slonik-MS-7971 rsyslogd: [origin software="rsyslogd" swVersion="8.16.0" x-pid="929" x-info="http://www.rsyslog.com"] start
Dec 16 16:55:50 slonik-MS-7971 rsyslogd-2222: command 'KLogPermitNonKernelFacility' is currently not permitted - did you already set it via a RainerScript command (v6+ config)? [v8.16.0 try http://www.rsyslog.com/e/2222 ]
Dec 16 16:55:50 slonik-MS-7971 rsyslogd: rsyslogd's groupid changed to 108
Dec 16 16:55:50 slonik-MS-7971 rsyslogd: rsyslogd's userid changed to 104
Dec 16 16:55:50 slonik-MS-7971 systemd-modules-load[219]: Inserted module 'lp'
Dec 16 16:55:50 slonik-MS-7971 systemd-modules-load[219]: Inserted module 'ppdev'
Dec 16 16:55:50 slonik-MS-7971 loadkeys[217]: Загружается /etc/console-setup/cached.kmap.gz
Dec 16 16:55:50 slonik-MS-7971 systemd[1]: Started udev Kernel Device Manager.
Dec 16 16:55:50 slonik-MS-7971 systemd[1]: Starting Remount Root and Kernel File Systems...
Dec 16 16:55:50 slonik-MS-7971 systemd[1]: Started Remount Root and Kernel File Systems.
Dec 16 16:55:50 slonik-MS-7971 systemd[1]: Starting Load/Save Random Seed...
Dec 16 16:55:50 slonik-MS-7971 systemd[1]: Starting Flush Journal to Persistent Storage...
Dec 16 16:55:50 slonik-MS-7971 systemd[1]: Reached target Local File Systems (Pre).
Dec 16 16:55:50 slonik-MS-7971 systemd[1]: Starting udev Coldplug all Devices...
Dec 16 16:55:50 slonik-MS-7971 systemd[1]: Started Load/Save Random Seed.
Dec 16 16:55:50 slonik-MS-7971 systemd[1]: Started Flush Journal to Persistent Storage.
Dec 16 16:55:50 slonik-MS-7971 systemd-modules-load[219]: Inserted module 'parport_pc'

How to understand what is happening.
ps
Itself ubuntu and grub are installed on ssd drive. Windows on the second, normal hdd.

Answer 1

Hi,
Here it is:
Device: /dev/sdb [SAT], SMART Prefailure Attribute: 1 Raw_Read_Error_Rate changed from
suspicious.
Or the screw is fraying or something else with SMART
It is necessary to do a long SMART test, maybe it's worth checking the cables, if they are long, then put them shorter.
In general, these are some kind of "iron" problems with the screws. And it is necessary to check SMART on all screws.

Answer 2

SMART Prefailure Attribute: 1 Raw_Read_Error_Rate changed from 117 to 118
Disk crashes.
It is advisable to buy a new one and transfer urgently valuable data from the old one.