Hi, After upgrading to SL, when using X11 I kept seeing "Atom list is not a multiple of the size of an atom!" in my system logs, and also noticed that copying between OSX and X11 was sometimes not working (especially when "Update Pasteboard immediately" was checked). The problem is with the following lines in x-selection.m: Atom a = None; if (pdata->length % sizeof (a)) { fprintf(stderr, "Atom list is not a multiple of the size of an atom!\n"); return None; } On i386, sizeof(a)=4, but on x86_64, sizeof(a)=8. However, it looks like pdata->length is always a multiple of an int (4 bytes) even on x86_64, so about half the time this check gets flagged and the code to check the clipboard type is not run. My suggestion is just to use sizeof(int) instead of sizeof(a). Looking through the server code, it looks like Atoms are always 32-bit anyway when compiling the rest of the server, and are sizeof(long) outside of the server. Here's a copy of the patch I used to fix pbproxy: --- xorg-server-1.4.2-apple47/hw/xquartz/pbproxy/x-selection.m.orig +++ xorg-server-1.4.2-apple47/hw/xquartz/pbproxy/x-selection.m @@ -228,16 +228,16 @@ get_property(Window win, Atom property, TRACE (); - if (pdata->length % sizeof (a)) + if (pdata->length % sizeof (int)) { fprintf(stderr, "Atom list is not a multiple of the size of an atom!\n"); return None; } - for (i = 0; i < pdata->length; i += sizeof (a)) + for (i = 0; i < pdata->length; i += sizeof (int)) { a = None; - memcpy (&a, pdata->data + i, sizeof (a)); + memcpy (&a, pdata->data + i, sizeof (int)); if (a == atoms->image_png) { @@ -440,10 +440,6 @@ get_property(Window win, Atom property, [self x_copy_request_targets]; } } - else - { - XBell (xpbproxy_dpy, 0); - } } /* Set pbproxy as owner of the SELECTION_MANAGER selection. With this patch, I was able to copy an image from the OSX clipboard to an X11 application (gnumeric), and later select this image in X11 and copy it back to OSX properly. I also removed a call to XBell in x-selection.m. For some reason, when I selected some text in an xterm (or other Xaw applications), whenever I clicked anywhere to un-highlight the selection the system would beep. This only seems to be happening in Xaw-based apps with "Update Pasteboard immediately" checked. The bell ringing was driving me crazy, so I removed the call to XBell which is probably not needed anyway. I hope this is useful, Martin