make that office machine a mac pro, not a power mac - what was I thinking?

Thanks Dan – on my first two attempts, Firefox did not even get to that point – i.e. downloading from Zotero server. It did BEGIN to respond correctly on the third try.
Here’s what I did. I opened Firefox, cleared all recent history under tools, and could then use Firefox as normal. I removed the Zotero local folder, placed it on my desktop, and temporarily renamed it as a backup. I then removed Zotero from Firefox by selecting “remove” under Firefox – Tools – Extensions. I download a new copy of Zotero and installed it into Firefox, which restarted as a normal part of that process. On the first two tries, after opening Zotero, I was able to open Preferences (having done nothing else in Zotero). Under Zotero Preferences, under the Sync icon, the following settings were checked ON: ‘Sync automatically, Sync attachment files in My Library using Zotero, Sync attachment files in group libraries using Zotero storage’. I selected ‘Restore from Zotero Server’, and then clicked the ‘Reset…’ button. On the first two tries, I got the Mac’s “spinning wheel of death” and Firefox froze. It stayed frozen. I eventually chose to end the pain by using ‘Force Quit’.
On the third try, I got to the same point ass above and all kept working after about 15 seconds of the spinning wheel of death. I chose ‘Replace Local Data and Restart Now’, and finally ‘Sync Now’ from the pop-up window. After a few moments, I saw the popup telling me that the local database has been restored. This did appear to be the case for the 1,000+ citations that I had under the 2 group libraries that I participate in. I am the originator for one of the groups, and we have purchased additional storage through Zotero for both groups. I knew that retrieving the 19.2 Gigabytes (mostly pdfs as attachments) from the storage server to my local lard disk would take a long time, so I left Firefox open and the computer on – for 2 days! The file update icon kept spinning, and a progress bar appeared, but never got past the halfway point. The next day, I needed to shut off the computer, but the progress bar still hadn’t budged.
On re-opening Zotero in Firefox later, the progress bar is gone, but the green arrow update icon is still spinning. I’m afraid to use Zotero to obtain more references and continue my research problem using this machine. My thought is to transfer the entire local Zotero Library from my office desktop Mac Pro to this laptop via a direct USB link.
What do you think?

Thanks Adam. Given that I'm dealing with 2 macs, I will probably use a direct wire connection from the 'donor' mac to the 'recipient' mac. Basically, the recipient mac is turned on in a way that makes it appear as a connected hard drive. This will be faster and more direct than transferring the Zotero folder using a USB stick. I'll report back to this post on the forums when I get into the office next week.