I have been using a Mozilla calendar since Sunbird version 0.2 and have not noticed this issue before recently. I am now running Thunderbird v.128.5.1esr (64-bit) with Calendar and notice a very long delay in loading calendar data which loaded fast enough in Thunderbird v.115.3.0. Now, running v.128.5.1esr and using "Find Events Pane" and selecting All or All Future Events, I can see that Calendar is expanding Events for each Repeat. If I set an event to repeat yearly for ten years, I find 11 entries in the Find Events Pane (Today plus the next 10 years). If I change Repeat to 50 years, I find 51. If set it to 150 years or to Forever, I find 101 entries. So it does not seem to expand more than 100 years. If I set the Event to repeat monthly, it still displays up to 100 years (set to Monthly for the next 10 years results in 120 entries). Events already entered prior to upgrading Thunderbird expand 100 years, new entries only get 99 years. This is happening with Events set for My Calendar (local) and also network CalDAV calendars. I realize I can set the Find Events Pane to anything other than All events or All Future events, but this does not keep Thunderbird from taking extra time to load all the calendar data. Changing these many events from Forever to a less "forever" amount of time is viewed as impractical (unless I find no other relief). The sort order selection in the Find Events Pane does not seem to hold through program restarts, either. Can anyone confirm these findings? Is there possibly a setting that would stop Thunderbird Calendar from processing Event Repeats beyond a set number of entries (In v.115.3.0, I find no future -repeats- in the Find Event Pane)? I experience this issue with clients running Windows 10/11 and a couple Linux boxes. Thanks.