00changelog.i unknown format

[Robert van Spyk]

Need some more information and possibly a fix for an error. I have been
using Mercurial Distributed SCM (version 2.8.2) and occasionally get a
repository acts corrupt with this error:

abort: index 00changelog.i unknown format 44748!

The referenced file does not seem to be corrupted but it is somewhat
hard to tell. The error occurs on every command I attempt and so far I
have not found any way to recover: always need to copy the .hg folder
from a clone.

Thank you,
Robert