Raspmc library export failure -- how to fix?

I’d like to upgrade to OSMC from Raspbmc, but saving the “watched” states of a large collection of videos.

According to the “Moving from Raspbmc” guide, I need to “export the video library”. (I assume that the whole point of doing that is to save the “watched” states although it doesn’t explicitly say so.) So I followed the guide which appeared to work, and in the home directory I find a folder called “xbmc_videodb_2015-05-08” containg a file “videodb.xml” containing just this:

<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
    <paths />

Something has evidently gone wrong since there’s no “watched” states in that.

I can see a sqlite3 database file at “/home/pi/.kodi/userdata/Database/MyVideos90.db”, 900kB in size, and a “strings” dump of that file shows that it contains the complete list of all my videos, so I assume that’s where the “watched” states are stored normally.

Suggestions on how to to export video “watched” states please.

The idea is to export fanart, scraped information etc. I am not sure if watched status is exported. You may be better just copying the MyVideos* database manually. Be sure to add your sources to the OSMC system first.