Hello, I have problems using the functions as.Date and strptime/strftime of base package and some functions of package zoo in my computer (Apple, Mac OS X 10.3.9). When I use them, the R application closes... However, it depends on the length of the vector I want to transform. For example, in the data.frame: climat[c(1:5,1460:1462),] date TEMP_STG PRECIP_STG 1 01/01/01 24.51 0.6 2 02/01/01 24.51 1.2 3 03/01/01 24.51 27.1 4 04/01/01 24.32 36.9 5 05/01/01 24.12 22.2 1460 30/12/04 25.32 0.0 1461 31/12/04 25.76 1.0 1462 01/01/05 25.88 0.0 class(climat$date) character If I do: date=strptime(climat$date,format="%d/%m/%y") then R closes. However if I do d=strptime(climat$date[1:5],format="%d/%m/%y") and then date=strptime(climat$date,format="%d/%m/%y") it works! (idem with functions as.Date, as.yearmon, etc..) I already re-downloaded R but it still doesn't work. Has this bug been reported? How can I overcome this problem? Thank you very much for any help! Natalia Norden Natalia Norden PhD student Laboratoire Evolution et Diversit? Biologique Bat 4R3 Universit? Paul Sabatier Toulouse III 118, route de Narbonne, 31062 Toulouse Cedex 9