Wiil appreciate any help in ridding myself of photos which I seem unable to synchronize ( the same 176 photos appear repeatedly) since i reverted from Mac El Capitan OS back to Yosemite. I presume it's because my Lightroom mobile had fewer photos with the earlier version I had gone back to with time machine.
Please follow the below steps.
> Sign out of Lightroom
> Restart Lightroom and Sign back in
If you still face the issue,
In Lightroom preferences > Lightroom mobile, press the Delete All Data button.
Note : This will delete all the synced data from Lightroom mobile.
Let me know if this helps.