If you are running anti-virus software, it may be worth trying to disable it for a short period to see if it helps. I wouldn't normally suggest this, but this slowdown has been reported before and confirmed in our own testing labs. I've scheduled work for the future to improve performance when running alongside anti-virus software. The reason the slowdown occurs is that anti-virus software adds another 'layer' between bliss and your music files, acting as a middleman as music files are read and written to. This makes bliss take longer to do its job.
Another reason can be if bliss is accessing your music files over a slow network. Wi-fi networks, despite making advances in speeds, are still much slower and less reliable than wired networks. If you are using a wireless network, try with a wired network to see if you get any improvement.
Any other FAQs I forgot or clarifications required? Post your ideas below!