If you are running Mac OS X 10.4 "Tiger" or later and have already been syncing your Palm OS device with this Mac, you must first perform one final sync with your existing setup before installing this version of The Missing Sync for Palm OS to ensure that your Mac contains the most current data.
Now, I am running Mac OS X 10.4 "Tiger" or later, and I have already been syncing my Palm OS device with this Mac. Despite having a reasonably strong suspicion that what the ReadMe meant was "If you ... have already been syncing your Palm OS device with this Mac using some software other than The Missing Sync...", I dutifully synced my Palm. Doing this brought up a warning that I occasionally see to the effect that some conflicts had been found between the PowerBook's and the Palm's calendars, and that they had been "repaired" (as an aside, I'd prefer to hear they'd been "resolved"—"repaired" sounds precarious), but that I would need to sync again. So, I did. And in doing so I learned that the Bluetooth connection between the Palm and the PowerBook has some kind of aversion to being brought back up after a recent use, so the two devices fought each other for a while before they agreed to sync again.
The second sync was just about to finish up, when the Palm end told me that it had lost the Bluetooth connection, and the PowerBook end just wedged and had to be forcibly quit. I am not making this up: I had to sync a third time. I let that complete, and ran the Missing Sync installer. While I don't mind the OS X installer, I much prefer applications that support drag-and-drop installation. But, as if sensing that I wasn't already regretting this upgrade enough, Missing Sync insisted I reboot the machine! Incredulous, I did so. Then I figured I'd sync once more for good measure. Two more problems turn up. Firstly, it seems the upgrade turned off Bluetooth as one of the acceptable syncing methods, so initially I sat there hammering away at the HotSync icon on the Palm, and repeatedly failing. Secondly, some kind of warning about syncing with desktop applications appeared—something I had already said was fine when I first installed Missing Sync. To be fair, the warning may have been issued by OS X assuming this was a brand new application, but losing my preference to use Bluetooth to sync is unacceptable.
The first sync with 5.1.1 just finished, and I have an error in the log:
SyncClient error. Mingling failed.
There's no indication whether this is minor or major. I suppose I'll just sync for a fifth time this afternoon and see if it goes away. I am perilously close to regretting I upgraded.