Dear all, is there an option to have Thunderbird sync network calendars once upon start? I have a couple of large network calendars and repetitive syncing causes performance problems, but on the other hand, if I set sync to Manual, Thurderbird does not sync upon start and shows only the events that had been cached locally (off-line) in the past, but not any events meanwhile added to the network calendar by other clients. Thus, I either have to remember to manually sync once every calendar after each program start, or I have to activet syncing every xx minutes, which causes the programm to periodically freeze for some time (during syncing). Is there any good solution to this? Is there maybe an option in the config editor "sync upon start"? Thank you very much.