Okay I'm having issues with my Lightroom. I can't seem to select multiple images to sync. I can only select multiple images that are next to each other. On my Apple keyboard I used to click on an image than hit the (fn) button on the keyboard and then select the other image. I can't seem to do that now. Is there a setting I accidentally changed?
You may try and reset the Lightroom preferences and check if that helps.
Also, you can check the correct workflow for sync settings in Lightroom.
The shortcuts for selecting multiple images are the same as they are in the Mac Finder and most other Mac programs:
On my Apple keyboard I used to click on an image than hit the (fn) button on the keyboard and then select the other image.
The Fn key is never used for multiple selections on a Mac, so if you're pressing that key, that's the reason it isn't working. Use the Shift or Command key.