User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.0; et; rv:1.9.1.1) Gecko/20090715 Firefox/3.5.1 (.NET CLR 3.5.30729) Build Identifier: 20090716031803 This causes the alarm to display and any action on it triggers modification_failed error, because there's no event any more. Reproducible: Always Steps to Reproduce: 1. Create recurring daily event on current hour with reminder 5 minutes before. 2. After save when reminder pops up choose snooze for 5 minutes 3. Delete all occurences of event 4. Wait until alarm pops up. 5. Click dismiss.

Currently alarms for repeating events are partly broken, see related Bug 494140.

Hi, I have the same issue on thunderbird + lightning User Agent : Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.1.8) Gecko/20100227 Lightning/1.0b1 Thunderbird/3.0.3 This happens when I have put the event remainder in snoozed state and then I get a mail for event cancellation. After I have deleted the event then snoozed alarm again pops up and gives the error mentioned in the original big report.

I can confirm that this exists in 1.0b2

Hi, I face the same issue on thunderbird + lightning Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110424 Lightning/1.0b2 Thunderbird/3.1.10 It can also be reproduced by using multiple alarms and deleting only the current occurrence of the event after the first notification but before the others.

This should be fixed by Bug 554267

Indeed, I'm unable to reproduce (both using original STR and these in comment #4) with a recent 1.0b4pre build :).