Subfolders don't sync, error: channel user@mail: near side box INBOX/subfolder cannot be opened

[gerazov]

After a few days of e-mails gone missing I've found the cause to be an update in isync - sharing here to make it easier to find if anybody gets stuck before the new isync version rolls out.

I have two machines using a mutt-wizard setup that sync IMAP locally. After a couple of days (since I updated my system) I noticed that I couldn't find emails I know I read or sent. It was hard to find the root cause but I finally tracked it down to a bug (feature?) in an update in mbsync (isync) that makes it fail syncing subfolders as it can't read them locally resulting in the error:

Error: channel user@mail: near side box INBOX/subfolder cannot be opened.

To make it work, as Oswald Buddenhagen suggests add "INBOX*" in your ~/.mbsyncrc in the Patterns section, i.e. it should now read:

Patterns * !"[Gmail]/All Mail" !"*fts-flatcurve*" !"*virtual*" "INBOX*"

And don't add an ! before it - it'll invert it, i.e. it wont sync any folders matching the pattern 😅

Also if you're using a dated version of mutt-wizard it would be wise to change the mapping of O in muttrc to show error messages (i.e. delete the 2>/dev/null), since if you're using a single machine you won't be aware that nothing gets updated on your server if you don't open the webclient ...

macro index,pager O "<shell-escape>mbsync -a <enter>" "sync all mail"