(MacBook Pro 2.16 GHz 3 GB, Snow Leopard 10.6.8, iCal 4.0.4) All the entries have disappeared from one particular week in iCal. Also, that week has become unmodifiable: if I try double-clicking to make a new entry, nothing happens. (I can make a new entry in the "All Day" row -- but then that entry is not deletable. However, if I exit and then restart iCal, that entry is gone.) All other weeks work just fine. I'm sure this is totally irrelevant, but the week in question is Sep 9-13, 2009. In Month view, all the days from Sep 9 through Oct 4 (the last Sunday on that screen) have this same problem. Also, the location of the "All Day" rows are screwed up -- in the middle of each "Week" row, rather than just under the date numerals. And the events in the first week (the "good" week) are also displayed lower down than they should be. And I can only get to that month by going forward from August. If I try going backwards from October, I can't -- although if I click the back arrow a second time it skips from October back to August. (Again, all other months are fine.) In Day view, all the original entries show up. But when I go to a day in that week and then switch to Week view, that day's event is repeated across that entire week -- and, as before, nothing is clickable. AARRGGHH!! Just for a few minutes, the problem got stranger: It suddenly became the week of Aug 31 to Sep 6 that has the problem and the previously problematical week is just fine ... then the week of Sep 14-20 instead ... then the original week ... back and forth ... and then clicking on the Back arrow goes to the *next* week and vice-versa ... !!! Exiting and restarting cured that ... for a few minutes. Now it's happening again! WHAT IS GOING ON??? (Later) I tried printing, and discovered that it's impossible to print the week Sep 7-13; it prints Sep 14-21 in its place. Then sometimes it prints other weeks correctly, but other times it prints the week a week later than what is shown on the screen. I've tried deleting and re-entering by hand all the events from the bad week and the week before it (when I access them in Day view) but that hasn't helped.