Last wednesday i got some updates for my W10 O.S. running on the I7 Lenovo laptop, and it asked to be restarted which i did.
After the restart i got the announcement in a blue screen the boot media could not be recognised....a 250 GB SSHD...
seemed the HD was converted to Linux and W 10 could not read the disk anymore.
Luckily i had an relative recent backup, so after thee Disk was repaired with a fresh install of W10 64 bits, i put the backup on it, and only lost 4 weeks stuff, nothing special.

The clou from the story except that windows 10 update can blow your disk is to have a recent full backup ready.