No notification for missed iCal event/alerts in Mountain Lion?

Me too.

What's worse is that appointments that run tasks don't run either. If you want a script to run daily at 7am, your computer must be on at 7am otherwise it skips it. I think the same is true for daily iTunes podcast updates.

This is probably because I'm using a 2011 model that doesn't use 'power nap' technology. In order to fix this you need to upgrade your hardware. Or downgrade back to Lion or Snow Leopard.

I think I hear Steve Jobs spinning in his grave.

Yes. I have ML 10.8.2 on a 2009 macbook pro. The Apple store genius was no help.

If I happen to be using my machine at the time, I'll see an alert in the upper right screen the correct amount of time before the item start. My choices are to close or snooze.

In the prior os, I could select from a number of snooze options and be reminded indefinitely. Now snooze will remind by default in 15 minutes even if the item starts the next day. Repeatedly snoozing in 15 minute intervals is dumb. Plus, if my machine is asleep, the alert will disappear at some point anyway.

If I do nothing, the alert counts down to the start time, displays 'now', and then disappears from the screen and notifications at the end time. Yet system preferences says notification alerts stay on the screen until dismissed. So even when my machine is awake, alerts still aren't persistent. Maybe it's a power nap and app issue as well? I sure won't regress os-wise. It took me weeks to recover from the last upgrade and compile a list of everytihing that went south.

I've gone low tech and keep a stack of old business cards on my desk. The backs contain all the appointments, events, and tasks I need to remember in chronological order. If an item can be postponed, I move the card to a second stack - my equivalent of indefinite snoozing while keeping the item in front of me. Periodically, I shuffle through this stack to see what I want to move to the top or act on. I'd try google calendar except from what I read on forums syncing between these apps is also problematic.

I have the same problem in Maverick..

I have a calendar event that is happening tomorrow at noon..

When I created the event I gave it an alert for 2 days before the event.

Yesterday at noon I got an alert as expected.

I snoozed the alert for 2 hours.

then an hour later I shut down my computer.

Today when I rebooted the computer, I got NO alerts for the event.

I open calendar and look at the event, and it shows two alerts, one for 2 days prior to start, and a second one for 2PM yesterday... But the comptuer was powered off at 2PM...

WHY isn't it showing me missed alerts when I start up the computer? I have other events happening later today, with a 8 hour prior alert, and they popped up right away this morning when I started the computer, 5 hours prior to the event...

It appears that alerts that are of the form "12 hours prior" WILL be popped up if you start the computer 5 hours prior to the event... BUT if you recieve a alert and snooze it then the alert is set to a fixed time "4/4/14 2:22PM" and if the computer is NOT active at that time then you will never see the alert....

Is there anyway to fix this? Any way to be notified of missed alerts? ... Or any suggestions for a better calendar app that supports alerts and snoozing them?

This is very frustrating for me also. What to do?