Post-upgrade syncfolder error: unsupported operand type(s)

Philip Hudson phil.hudson at
Sun Jul 27 03:20:25 BST 2014

Running debian testing, and became aware of how woefully outdated the
version of offlineimap in the repo was, so I apt-get removed it,
downloaded the current release tarball, and did the 'make' and 'sudo
python ./ install' incantation. All seems well with the binary
in the new location of /usr/local/bin (the debian one had been in

I'm syncing with GMail in what I take to be a fairly standard setup.

On first run post-upgrade, I get an error about certificates, which I
fairly quickly find the solution to. Hooray!

On second and every subsequent run, I get the following error for
multiple folders:

ERROR: ERROR in syncfolder for GMail folder MyFolder: Traceback (most
recent call last):
  File "/usr/local/lib/python2.7/dist-packages/offlineimap/",
line 450, in syncfolder
    remotefolder.syncmessagesto(localfolder, statusfolder)
  File "/usr/local/lib/python2.7/dist-packages/offlineimap/folder/",
line 780, in syncmessagesto
    action(dstfolder, statusfolder)
  File "/usr/local/lib/python2.7/dist-packages/offlineimap/folder/",
line 713, in __syncmessagesto_flags
    addflags = selfflags - statusflags
TypeError: unsupported operand type(s) for -: 'list' and 'set'

  unsupported operand type(s) for -: 'list' and 'set'

I'm hoping it's a versioning issue with a library dependency -- some
standard Python library that Offlineimap uses and debian only provides
an out-of-date version of. My Python knowledge is virtually zero, so
I'm not confident about debugging the issue myself.

I do have a which is imported in my .offlineimaprc,
containing code culled from the Interwebs for things like getting
credentials from Emacs or from encrypted .netrc/.authinfo files. It
worked fine with the previous release. The only change I've made in
between is to insert (and comment out) the encrypted netrc code, so
unless I've tripped up over some aspect of Python's
whitespace-awareness that I'm not aware of, I'm assuming that can't be
the cause.

Phil Hudson         
@UWascalWabbit                 PGP/GnuPG ID: 0x887DCA63

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