I've installed a stand alone copy of Lightroom 6 on mac OS X 10.10.3 (Yosemite), but the Update option in the Help toolbar is greyed out. Is this because there are no updates available at the moment, and the program will inform me when updates are available, or do I have to do something to bring the option back?
Solved by closing Lightroom, deleting the following file:
<Startup Disk>/Library/Application Support/Adobe/AAMUpdaterInventory/1.0/AdobeUpdaterAdminPrefs.dat
and then installing the update manually from the Adobe downloads page. Restart Lightroom. The Update button in the Help toolbar tab now works properly and performs a check for updates.