[Brian]

Hmmm. That message has to do with writing to the OmniFocus database on that particular machine, not with syncing. I suppose the absence of syncing over the weekend will cause more zip files to build up, but I wouldn't expect that to cause the message unless your database was pretty large.

Have you ever used the "archive old data" command? If not, there may be a large number of completed actions that are still stored in your database. I guess it's possible that could eventually cause the cache writes to bring up that message.

If you've never used it, I'd suggest trying that on your home machine - it'll move older completed actions over to a second database that isn't synced to the work machine. (I have a recurring item in OmniFocus that reminds me to use this once a month.)

If that doesn't resolve those messages, as an experiment, if you leave OmniFocus running over the weekend on your work machine, does the message still show up on Sunday?