Hello. Using DT register for the first time... that sync tool is not needed. Don't worry about it. Once you remove the old JEvents version, you won't see that tool anymore. Check out our video tutorials to learn how things work and get everything setup. Thanks!
We actually just took over the site management, and noticed an old events and dt register module, which we are updating , which is why we installed the new events , and upgraded to a new DT Register, so yes we do have some old events that need to be sync'ed but the button does not fire.
You should not even need to use that anyway. The new JEvents has a tool "Migrate Legacy Events". Use that to pull your old events into the new JEvents. Everything should be fine with DT Register already. IF you notice anything goofy, then follow the details in the sticky post in this forum about jevents not being in sync. Don't worry about that sync tool though. It is rarely needed... and is NOT what pulls your events into the new JEvents in the first place.