Recovering damaged agent groups

[Robert Epprecht <epprecht@logon.ch>]

Hello,
I need advice how to recover some agent groups after an accident.

While downloading I ran out of disk space (shame over me, didn't run
gnus-agent-expire for quite some time). Maybe also the fact, that my
connection to the ISP had broken down while downloading a few minutes
ago contributet to the disaster... After cleaning my disk and running
gnus-agent-expire I tried to read news. But now my agent is very con-
fused and doesn't work any longer the way it should.

gnu.emacs.help (thats likely to be the group, that was downloaded when
the crash occured), showed (only) the ticked articles the normal way,
but all the others where marked '@'. Articles that had been downloaded
in a prior session where also marked '@' but could be read normally.
New articles (marked '@' too) where not yet downloaded (gnu.emacs.help
runs under the predicate 'true'). I marked them all with '%' and down-
loaded them. After that they where still marked '@' and 'SPACE' or `n`
sayd that there where no articles left. But 'RET' worked now, and so I
could read and save them.

Now the situation is different:
Groups that where downloaded *before* gnu.emacs.help still work.
gnu.emacs.help: 'g' increases the number of unread articles shown in
the group buffer, but if I enter the group there's nothing there (only
a dormant article). It also seems, that all the groups coming *after*
gnu.emacs.help are not downloaded.

What can I do to fix these groups?
(I'm running Gnus 5.6.42 in GNU Emacs 20.2 on Linux)

Any help would be appreciated very much.
Thanks a lot!

Robert Epprecht