What if chkdsk already borked your system?
Assuming you’re staring at a system that refuses to start up like it normally would, don’t panic. Or, rather, you’ve probably already been panicking, so it’s good that you’ve gotten most of the stress out of your body already. There is a fix for the issue, even if you can’t get into Windows 10 to address it with any lingering updates. As Microsoft describes:

The device should automatically start up into the Recovery Console after failing to start up a few times.
Select Advanced options.
Select Command Prompt from the list of actions.
Once Command Prompt opens, type: chkdsk /f
Allow chkdsk to complete the scan, this can take a little while. Once it has completed, type: exit
The device should now start up as expected. If it restarts into Recovery Console, select Exit and continue to Windows 10.