I though this was an issue with the Oculus version of Minecraft so I tried to run the regular version but it said my trial had expired. (Not sure why I need to pay for the Oculus version as well the non-Oculus version). So I purchased the regular Window Minecraft and it worked - for a while. Then suddenly in the game I could not save or interact with anything - only move and look! So it occurs to me that the game may be reverting to 'your trial period has expired' mode! So now despite paying for both the Oculus and regular Windows Minecraft I cannot play either!

Update: I re-installer the software and discovered that the problem does not happen with a newly generated world, only my saved one.

I then deleted the world_behavior_packs.json and world_resource_packs.json files from my saved game and the problem was resolved (at least for the short time I played) The first file only contained the word 'null', and the second:

[

{ "pack_id" : "d20460fa-3984-4f17-bbd1-26174f8444dc", "version" : [ 1, 2, 4 ] }

]