Travis651 Said:
"Magic Keyboard and Mouse slow to connect: [...] Anyone have any advice?"
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Troubleshooting a Lagging Keyboard and Mouse Connection:
A. Change the Battery:
There may not be enough power for it to pick it up right off the pat. So, put new batteries in there.
B. Verify Compatibly:
If incompatible, it is not expected operate as desired. So, verify if this is compile with your macOS version. Being Apple it seems it would be, but verify, nonetheless.
C. Try Safe Mode:
In Safe Mode, login items do not run, and corrupt system files(i.e. caches) are intentionally reset as a way to fix issues
- Boot: in to Safe Mode: [Hold Down: shift key upon boot].
- Log in: as same user
- Wait: 30 seconds
- Restart; your Mac
- Log in: as same user
D. Remove Login Items:
While in Safe Mode, remove all of your Login Items, and then restart the Mac. Go Here: Change Users & Groups Login Items Preferences on Mac - Apple Support