Tell us the account you want to use to open _vti_rpc.

I noticed I had an additional OneDrive account listed in Connected Services which wasn't connected. I deleted it and that seem to have fixed the problem.

I still get this error every day after the last windows update.

Some people solved it by checking that the "connected services" matched their office account, but for me they are both the same.

Very frustrating there is no help or solution from MS - this is 100% reproducible (and they can use my machine if they want)

Looks like disabling "use office 2016 to sync office files I open" solves this bug (or at least a workaround). It is disappointing that MS cannot come up with any advice or a fix, that we have to figure it out on our own.  

The question now is what did "use office 2016 to sync office files I open" actually do? I.e. what functionality have we now lost?  Surely if you save a file on onedrive, it is synced, and if you save to local FS, it is not -  simple as that. What could this check box actually do to change this behaviour?

For me, onedrive has been a constant source of problems, including sync conflicts and unsyncable files when I am a single user who doesn't share a single file with anyone else. It is so easy to break onedrive, just create a folder and immediately rename it - result is a conflict which onedrive cant handle. It seems to have no concurrent locking or concurrent protection, even for a single user let alone multiple users.

So disabling "use office 2016 to sync office files I open" might actually make onedrive and office more reliable.

My connected service also matched. My problem disappeared and I didn't do anything. They're probably fixing the bug.

Yes, me also - the bug appeared to get fixed 3-4 days ago as a matter of due course.