On this page https://support.mozilla.org/en-US/kb/thunderbird-and-gmail?esab=a&as=aaq#w_archiving-messages I read: "Note that the Archive options... button is disabled for Gmail accounts, as it is not necessary to define the archive granularity with Gmail." Unforuntately, Thunderbird is not using a sane default setting. It's lumping all the emails into the Archives folder, making it very large and very slow. I would like to separate the archives by month. On my Hotmail account I could open the Archive Options and set it to archive by month. This button is greyed out for my Gmail account. I read that this is because of technical limitations, but that some users were able to get around it by setting a configuration options "mail.server.serverX.is_gmail" to false. However, I also found this bug: https://bugzilla.mozilla.org/show_bug.cgi?id=724418 Does this mean Thunderbird will not respect changing the configuration option? I really need the monthly archiving capability, so I may have to forward my GMail messages to my hotmail account, if this is a GMail or Thunderbird technical limitation. Is there an easier way, though? Thanks in advance!