Your browser does not seem to support JavaScript. As a result, your viewing experience will be diminished, and you have been placed in read-only mode.
Please download a browser that supports JavaScript, or enable it if it's disabled (i.e. NoScript).
This has been solved in 6.1 so just wait for the final release.
In the meanwhile, don't use this sort, and if you're already crashed, just remove the <system>.sort=<digit> from the recalbox.conf file.