You have used the terms archive and Compact. These are two completely different items. Compacting removes messages that you have marked for deletion. It has noting do do with compressing files to save space.

hi again, sorry for being so succinct(confuse) in my previous post. so I'm trying to achieve my sent emails (want to keep them all) but I'm getting the mentioned alert message. so what I tried is to delete few messages and then compact, as mentioned in the alert. but still was not able after to archive the rest pf messages as I'm getting the same alert ... hope this is clearer. looking forward to a solution. alex

You can use the actual Archive built into Thunderbird.

Right click the account in the Folder Pane and select Settings. Then go to Copies and Folders to set archive options. Selecting files and pressing the letter a will archive messages.

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

The other option is to create a folder under Local Folders and move some messages there.

hi again, sorry, tried all this but still getting the same error message, even if trying to manually archive the email. what I could notice so far is that some of the "sent emails" can be archived and some not. also, seems that sent email containing attachments are problematic although I cannot archive also few mails without the attachment ... what else can i try? alex

are you archiving to a sent folder as well as from one? Right click the folder and select properties. What is the size of the folder on disk?

Hi Matt,

"Q - are you archiving to a sent folder as well as from one?" A - yes

"Q - Right click the folder and select properties. What is the size of the folder on disk?" A - the size on disk of the sent folder is 3,1G with 6364 messages The sent folder in Archives - size on disk 4G with some 16000 messages.

hope this helps.

oh, btw, I changed recently the machine and used TimeMachine to transfer all data. could this be the problem?

thanks,

The 4Gb files your trying to archive to is the issue. Rename the folder sent -old (or something similar that has meaning to you and then archives will be back on track. 4Gb is the upper limit of what a folder will hold at this point in time.

awesome, it worked! thanks,

Do I understand this right?: Inbox and Send in each account are limited to 4 Gb, but you just move mail to other mailboxes because their size is not limited.

Medica said

Do I understand this right?: Inbox and Send in each account are limited to 4 Gb, but you just move mail to other mailboxes because their size is not limited.

I am using POP. Aren't they all "Local Folders"? Then, I imagine the same: Inbox and Send limited to 4 Gb, but other folders not size limited, and no need to put other folders in "Local Folders". (??) Also, one doesn't generally mix multiple accounts in "Local Folders", right?

Where are the mail folders stored? Should users make independent backups in addition to "Archive"?