I recently deleted a large number of old e-mails from both my online e-mail accounts and from my Thunderbird local folders. I have now only about 10 e-mails between my online accounts and my local folders. The size of my profile directory was multiple GB before doing this.
In order to reclaim space, I understand that I should "compact" the folders now, following this large deletion. To attempt to do this, I have selected "File", then "Compact Folders". I also selected "Compact" from the context menu of each local folder. The size of my profile directory is still multiple GB in size.
I have tried restarting Thunderbird (version 38.3.0), updating it and rebooting, but the size does not change -- in spite of there being no way that the e-mails there are taking up that much space.
How can I force Thunderbird to compact the necessary folders?