A few months ago, when I was trying to move Alfred to a new Mac, I was unable to do so -- I tried syncing via Dropbox, but I could not get the new Alfred install to pick up all the preferences I'd created, and nothing I was told on this forum worked. So for those few months my new machine sat unused, as I was too busy with work to invest any more time until things slowed down. Now I am once again trying to move to a different new machine, took all the forum advice to heed, making sure my preferences were completely synced before installing on the new machine and setting Dropbox on the new machine as the location of my preferences. Then I copied my Powerpack license and pasted it into my new installed Alfred on the new Mac. However, when I went to use my old Alfred, it had lost THREE YEARS worth of customization! GONE! Now both installs are worthless, since it is the customization that gives them utility. I'm too drained at this point to deal with Alfred any more -- there have to be similar apps that won't create these kinds of tragedies. I don't know why I couldn't attach my preferences file to an email, and then paste it into a specific folder where my new installation would find it, i.e., keep it simple.
Anyway, good luck to you RussB, I hope you had better luck than I.