OK, MongoDB version is 3.2.16, also tried with 3.6.4. This is my keycloak-server.json config: https://pastebin.com/vx8ip8Z1 It is working fine with 1.9.8, I am able to export both to single JSON file as well as to directory. Exported file/folder contain all realms and user accounts. Now, when I am trying to run 2.0.0 against the same config, it gives me following error during the startup: https://pastebin.com/BNjXQ5ac similar error appears with 2.1.0: https://pastebin.com/TJUE83Fa And then it is working back again with 2.4.0 (still against the same config file), but export DB grows from 3.7MB to 76MB. Events collection is the biggest one - 65MB. And then both 2.5.0 and 2.5.5 won't see realms, no matter which version of Mongo-java driver is used, bundled 3.2.0 or 3.2.1. https://pastebin.com/LqFHYcJu However, I can see user accounts and realms in .bson file. Any idea? brgds, Dnia Wtorek, 1 Sierpnia 2017 18:17 Bill Burke <bburke(a)redhat.com&gt; napisał(a)