Batch job on Mac -- Calendar always launches it twice

[literalzebra]

I've run into a serious problem scheduling a nightly backup on my Mac. I had this problem on my previous Mac, but I recently did a fresh install on a brand-new Mac and the same problem continues so thought I'd post here.

I follow the instructions for scheduling a backup using Calendar at: https://freefilesync.org/manual.php?topic=schedule-batch-jobs#macos

But the problem is that Calendar always launches the backup job at least twice. E.g. if I create a daily backup event at 3 am that is 1 hour long, it launches it at 3 am and then again at 4 am. In calendar, I've selected "Alert: Open File (At Time of Event)".

I've tried playing with the Calendar settings, and if I make the event only a half-hour long, then it launches the backup at 3:00 and then again at 3:30. If I set it to open the file e.g. 15 minutes earlier, it runs backup... wait for it... *five* times. I wake up, and there are five "backup completed" windows I have to close.

If I leave my computer on overnight and backup takes less than an hour, it's not really an issue. The problem is when I open my computer in the morning and it starts two backup jobs simultaneously, and I have to assume they're interfering with each other. Or when backup takes more than an hour.

I can't find any other reference to this on the forums here -- I thought it was a quirk of my old Mac, but now that I bought a brand-new one and installed everything fresh and still have the same problem, was hoping somebody could help?

It seems to be a bug more with Calendar than FFS -- the bug existed in Big Sur and now I'm finding it in Monterey -- but perhaps someone can suggest an alternative to Calendar for daily scheduling?

[xCSxXenon]

Well I can't quite help with the Mac issue, but FFS uses 'lock' files to prevent multiple syncs running at the same time on the same locations, so you shouldn't worry about interference.

[literalzebra]

Thanks xCSxXenon -- I'm not so sure about the locks though. When I opened my computer this morning, it was indeed running the two identical backup jobs simultaneously -- each one was in the middle of copying a different file. Are you saying that's not supposed to happen?

[xCSxXenon]

That is not supposed to happen. The locks can be disabled, but definitely not on accident.
https://freefilesync.org/manual.php?topic=expert-settings

[literalzebra]

Huh, thanks. I just tried running the batch job manually twice right now, and indeed the second one says "waiting while directory is in use". Which was definitely not the case this morning, there were two simultaneous file copy operations happening. Maybe a race condition since Calendar presumably started the two backups instantaneously?

If the simultaneous backups happens again, I'll start a separate thread here. If there are any log files I can submit for debugging to help understand how it happened this morning, I'd be happy to as well.