Can anyone offer any suggestions?

Suggest you archive all emails older than a month in the Sent folder to reduce the file size.

set up Archive options:

• https://support.mozilla.org/en-US/kb/archived-messages

then report on results.

That suggestion did not help. I actually just cleaned out the Sent folder completely and am still encountering the error.

Also, Thunderbird has stopped receiving new emails unless I close and restart the program. It will not download new emails automatically nor will it if I click on the Get Messages button manually.

Any other suggestions?

Thanks.

Any suggestions? Anyone?

what mail providers?

re : I have "place a copy in" and "Sent Folder on" for both accounts checked.

Tools > Account Settings > Copies & Folders Suggest you try: Select : 'Place a copy in' Select: 'Other' and 'Sent folder on imap mail account.'

OR if gmail, then uncheck 'place a copy in' s they auto put it in the Sent folder. click on OK

some add'l info and a conclusion after testing different configurations:

i'm using TB 31.8 on linux mint 17.1 using pop3 to pick up emails from a rackspace account. i have installed no addons i am using auto-spam-detect

CONCLUSION after testing many different configurations over several days, i have determined that auto-spam-detect is (at least, is complicit in) the problem. after i turned off auto-spam-detect, the problem has gone away. more testing is needed to determine what aspect of spam detect causes this issue. it appears that it controls some common element of several features of TB, and when it cannot successfully complete its task, it locks up and those other features cannot work.

SYMPTOMS when sending an email, TB reports an error saying it cannot copy the msg to the Sent folder.

when this happens, new mail cannot be gotten from the mail server. furthermore, cannot delete either with delete button or right-click->Delete. also cannot right-click->move.

when selecting emails, the body of the newly clicked email does not appear in the bottom window - only text of originally clicked mail. clicking another folder then clicking Inbox fixes this.

after trying the Sent folder, a dialog box asks if cancel or retry: clicking retry seems to have no effect. clicking the 'close window' button on the new email window results in a dialog to copy to the Drafts folder - clicking 'save' again seems to have no effect. the new email window does not go away, and the 'Send' button on it is grey'd out. clicking the 'close' button again results in a popup dialog that says,

   'TB is currently in the process of saving a message.  Would you like to wait until the message has been saved before quitting or quit now?'

clicking 'cancel' at this point causes TB to complain it can't copy to the Drafts folder as well. clicking 'retry' results in

   There was an error saving the message to Drafts. Retry?

clicking 'retry' causes the new email window to close but no copy appears in Drafts.

clicking the 'Write' button on the main window will now open a new mail window, but the Send button is grey'd out. this mail can't be copied to the Drafts folder either. furthermore, nothing shows up in the error console.