I have just over 500 contacts and I want to resolve duplicates and each time I click to merge the duplicates it seems to start but then takes ages to seemingly make any progress. After 24 hours the process is still continuing with the progress bar still on the screen. I then give up and force a quit.
How long should it take to merge the duplicates? Say 60 or so fo them?
A few moments, reboot your computer and try again.
If the problem is still there, try booting into the Safe Mode. Shut down the computer and then power it back up. Immediately after hearing the startup chime, hold down the shift key and continue to hold it until the grey Apple icon and a progress bar appear. The boot up is significantly slower than normal.