Systemd hangs on mounting partition

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https://bbs.archlinux.org – I have switched to systemd and everything in fine, but my boot process hangs when it tries to mount /dev/sdb1 (500gb.mount) and asks if I want to enter in emergency mode or just to continue with boot... If I continue (pressing CTRL-D) or if I enter the emergency mode then exit without doing nothing, the partition is mounted without errors and everything works perfectly.That said, I think it's a timing process...I have to slow down the boot process and wait for /dev/sdb1 to be "free"...Maybe it's my fault: in my /home (on /dev/sda3, mounted without errors) I have some symlin (HowTos)