EFSTMPWP taking up whole drive possibly after failed win 10 update - What to do?

Hi,

I was hoping someone could help me...

I left windows 10 updating yesterday when I left work and when I returned today there was a message informing me it had failed due to no disk space and the entire C drive was full. Error code was 0x80070070

I clicked through the "manage storage" steps to find that in the section classed as "other" there are 2 massive files in a folder named EFSTMPWP taking up like 364gb.

I have searched online and learned that these are temporary files usually made by CIPHER(?) if you've tried to wipe the computer, it should delete automatically, but if the process is interrupted then it can remain..?? and the advice online is that they can be deleted.

This computer is actually a new purchase, a manufacturer refurbished PC that I only acquired yesterday, and as it turned out, annoyingly, there was a user account on it, which I deleted.

My questions are:

• Is it actually okay to delete these files? ...364gb is just crazy
• Is the creation of the EFSTMPWP files likely to do with the failed Windows 10 update, the deleted user account, or perhaps, the refurbishment (assuming someone did actually wipe it)?
• If anybody thinks it is likely the update (which I have tried a couple times to no avail) - Any advice on why it may not be working - It's trying to update from like version 10000 - 16000 (or something)