It appears that unfortunately, you have been impacted by a rare issue in our latest OS.
This error is recoverable but it will require you to use a USB flash drive (empty/blank one) to perform a procedure, all the details can be found in the post below:
More in-depth steps also provided a bit further down the thread:
Apologies for this inconvenience, do let us know if any of the steps are not clear or you run into further issues and we can certainly clarify.