How to reduce Postbox memory usage by unsubscribing from overstuffed folders

July 7, 2012 Postbox Airbrake

TLDR: I reduced Postbox memory usage from 500M to 150M by unsubscribing from one folder and cleaning out Trash. Here’s how.

For the past year I’ve been a devoted user of Postbox, an email client for Windows and OS X based on Thunderbird, but vastly improving on it, especially in the interface department.

What I’ve learned that if your Postbox is running slow, or consuming too much memory (I’ve seen numbers up to 500 Mb), most likely it’s not Postbox’s fault, but your mailboxes having too much mail in them. While you can blame Postbox, Inc. all day long for not coping better with large amounts of mail, it would be more productive to clean up your inboxes instead. Inbox Zero for the win!

Unfortunately, there is no way – within Postbox – to find out which folders take up most of the space. Fortunately, mail folders are stored as separate files on disk.

First, get JDiskReport, which “enables you to understand how much space the files and directories consume on your disk drives, and it helps you find obsolete files and folders.”. Just what we need, and it runs on both Windows and Mac.

Next, run JDiskReport on your Postbox profile folder. If you’re on Mac, it’s at (home)/Library/Application Support/Postbox. On Windows, it’s at C:\Users\(you)\AppData\Roaming\Postbox.


JDiskReport (this screenshot was taken after cleanup)

When JDiskReport is done, switch to the “Top files” tab. (Keep in mind that Postbox mail folders are stored as files on disk.) Now you can see what eats up your memory.

In my case it was a folder that received error reports from Airbrake. Ironically, I never looked at the emailed error reports, using the web view instead, and the emails were automatically marked as read. This error folder alone took up more than 1G of disk space, slowing down Postbox and eating up memory.

What remains is to go to Postbox and either unsubscribe from those folders (if your using IMAP), or empty them. Don’t forget to “compact” the folders after emptying.

Restart Postbox to see the difference.

Good luck.

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