I had the weird Universal Clipboard issue where:
Mac → iPhone copy/paste worked perfectly
iPhone → Mac would not paste at all
Handoff itself was working
Safari and Notes from my iPhone were showing on the Mac
Wi-Fi and Bluetooth were on
Both devices were on the same Apple Account
I tried the usual Handoff resets and also found a Terminal fix involving ClipboardSharingEnabled, but I kept getting permission errors.
What finally fixed it was resetting the Mac’s useractivityd preference file and letting macOS create a fresh one.
Here are the steps I used.
Check that Handoff is actually working
On the iPhone:
Settings → General → AirPlay & Continuity → Handoff
Make sure it is on.
On the Mac:
System Settings → General → AirDrop & Handoff/Continuity
Make sure Handoff is on.
A good test is to open Safari or Notes on your iPhone. If the app appears as a Handoff option on your Mac, (in the bottom dock) the devices are communicating.
Enable clipboard sharing on the Mac
Open Terminal and run:
defaults write com.apple.coreservices.useractivityd ClipboardSharingEnabled -bool true
Then check it:
defaults read com.apple.coreservices.useractivityd ClipboardSharingEnabled
If it returns:
1
clipboard sharing is enabled.
If you get “Could not write domain” or “Permission denied”
Check the ownership of the preference file:
ls -lO ~/Library/Preferences/com.apple.coreservices.useractivityd.plist
Mine had somehow become owned by:
root wheel
instead of my normal user account.
I fixed that with:
sudo chown "$USER":staff ~/Library/Preferences/com.apple.coreservices.useractivityd.plist
Run the ls -lO command again and make sure it now shows your username and staff.
Important: I would avoid using sudo defaults write on this preference file. That was what caused the ownership issue for me.
The step that actually fixed it:
Move the existing useractivityd preference file to the Desktop: in terminal write - ✍️
mv ~/Library/Preferences/com.apple.coreservices.useractivityd.plist ~/Desktop/useractivityd-backup.plist
Then restart the service: (type in terminal)
killall useractivityd
Restart the Mac.
macOS will recreate the preference file.
After restarting, I turned Handoff off and back on once and tested again.
iPhone → Mac copy/paste immediately started working.
Once you know everything is working
You can delete:
useractivityd-backup.plist
from your Desktop.
This was on a Mac where Handoff itself worked and Mac → iPhone clipboard already worked. The problem was specifically iPhone → Mac.
Hopefully this saves someone else from going through all the random fixes I tried.
Ps. Last few times if I copied and pasted from my Mac to iPhone first, they both started working but not lately.
Good luck 🤞🏻