It seems to me that the gbrowse_clean script is not quite as smart as it ought to be. That is, with regards to session variables, the GBrowse.conf file says in the comments that it will pick defaults for you, and while it does seem to do that correctly when the CGI is running (that is, GBrowse correctly stores the session database is a reasonable place), the gbrowse_clean script doesn't seem to know how to do this. A workaround is to uncomment the two session variables that appear first in GBrowse.conf. That is, uncomment these two lines:

session driver = driver:file;serializer:default

session args = Directory /var/lib/gbrowse2/sessions

and verify of course that the directory listed is where the session database is actually stored.

GMOD / GBrowse

gbrowse_clean.pl doesn't always remove old sessions #44

session driver = driver:file;serializer:default

session args = Directory /var/lib/gbrowse2/sessions