Yandex account causes a high CPU load and produces too many log records


I have noticed that a Yandex account causes a high CPU load in one of the syncing processes. When I’ve looked at logs I discovered that those related to the problematic account are much bigger and longer. The problem occurs both on Windows and on Linux. Please look at the logs attached.

Email Provider

Specific to one of email providers (Yandex Mail). Other email providers (Gmail and self-hosted one) works flawlessly.


  • OS and Version: Linux (Ubuntu 18.04, snap) and Windows 10
  • Mailspring Version: 1.6.3

(Originally posted by h31 on GitHub.)

Oh this is interesting - does Yandex support labels of some kind (or “virtual folders”?) It looks like Mailspring is discovering the same email message in more than one folder, and it’s thinking that the items were “moved” between the folders. Then it syncs the other folder, finds them again, and moves them all back over and over.

I’ll see if I can fix this once and for all later this month—Mailspring was built on the assumption that folders hold messages, and a message won’t appear in multiple folders, but it turns out there are several providers (maybe Yandex too) that implement “labels” or “tags” by just duplicating the message into several IMAP folders, and it really throws off Mailspring. Stay tuned—

(Originally posted by bengotow on GitHub.)

Hello, Ben. Thank you for the reply!

There is something named labels in the web interface, but I only see two existing labels - “Important” and “Unread”. There’s an action to add custom labels, but looks like I haven’t used this feature. And there is no IMAP folders for those labels. At least, I haven’t found.

(Originally posted by h31 on GitHub.)