New Win 10 Update today Feb 6th, comes with a warning.

[Saltgrass]

This updated installed this morning (KB4090913) and worked OK on one of my systems, but it does have a warning regarding the "Inaccessible_Boot_Device".  It might be a good idea to check the referenced KB to see if you can do anything to protect yourself.

After installing this update, some devices may fail to start, and return INACCESSIBLE_BOOT_DEVICE. This issue occurs when the windows update servicing stack incorrectly skips installing the newer version of some critical drivers in the cumulative update and uninstalls the currently active drivers during maintenance.

Microsoft is working on a resolution and will provide an update in an upcoming release. Workaround steps are available in KB4075150.

[fireberd]

This has been a known problem, for some, since it was first introduced in February.

Best option, before installing it, is to make a full hard drive (or SSD as applicable) backup (disc image) to a separate drive using a program such as the free (and popular) Macrium Reflect.  Then if it causes a problem you can restore the drive back to how it was before the update.  

Many users do not do it but backups are a must, not for "if" its ever needed but for "when" its needed.