Richard Pieri <ratinox@unilab.dfci.harvard.edu> writes:
   I just stumbled into a nasty gotcha, a conflict between Gnus (probably
   any version) and any on-the-fly file compression hooks. This morning,
   the code that pulls the system mailbox into a local Incoming file
   created a file called Incominga003.Z. The problem should be apparent:
   the .Z extension gets the file flagged as compressed, so the
   compression code tries to decompress it; since it is not compressed,
   this fails.
   
   The solution: do not allow periods in the pseudo-random Incoming file
   names.
   
   Editor's note: Similar behavior has been observed with jka-compr as
   well.
   
   This problem has been fixed in Gnus 5.4.