It appears in grub before Ubuntu starts (at the point where you can choose OS). You'll see a "Ubuntu, memtest86+ (on /dev/sda1)" entry (or similar). Unfortunately, since this is lilkely to be a hardware error, I'll have to reject this bug. If you let the test running overnight (or at least two passes) and it turns out OK, and Ubuntu still hangs, please comment and reopen the bug! Thanks for reporting this!
** Changed in: Ubuntu Status: Needs Info => Rejected -- System Boot hangs when the RAM is changed. https://launchpad.net/bugs/58377 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs