Hello,
I have a CalDav server at home. My laptop (win7, Outlook 2010, CalDav sync 2.27.0.0) works good there.
When leaving home the home server is unreachable so synchronizing results in an error.
Then I configured both Synchronization Profiles for interval 'manual only'.
I notice that both accounts still are being synchronized. The interval appears to be about 30 minutes. After that, the error log screen pops up on top of my work.
I was hoping that the inconvenience of manual synchronizing would stop these errors but that is not true.
Better solution would be detecting the home network, or the presence of the CalDav server (like the Internet check, ping 'server').
But at least a Manual synchronization interval should do nothing.
-zaadstra
Then you need to disable the general option "Trigger Sync after Outlook Send/Receive and on startup". That's the only way a sync is triggered with the manual sync interval.