Can't delete lists from my contacts on my Macbook M4 Air.

Based on everything you have described, I suspect this is an issue with how Contacts on your Mac is accessing or managing your contact lists, rather than a general Mac setting you’ve accidentally changed.

The most important clues are that you cannot delete or rename lists, dragging contacts into lists does not work, and yet all three operations work on your iPhone running iOS 27. 

This suggests we should investigate which account owns the lists and whether Contacts on your Mac is functioning correctly.

Here is what I would try, in this order.

Check which account contains the lists

Open Contacts on your Mac and examine the sidebar. Do your lists appear under iCloud, Google, Exchange, or On My Mac?

Apple explains how Contacts handles multiple accounts here:

Apple Support: Add contacts from iCloud, Google, and more to Contacts on Mac

Different account types can have different restrictions on list management. For example, Apple notes that Exchange contacts can belong to only one folder at a time.

Test whether the lists can be managed on iCloud.com

If the lists are under iCloud, sign in at iCloud.com/contacts using the same Apple Account.

Try renaming one duplicate list and, if appropriate, deleting it.

Apple provides instructions here:

Apple Support: Create and manage lists of contacts on iCloud.com

If the lists can be managed on iCloud.com but not on your Mac, that would point toward a problem with the Mac's Contacts app or its local synchronization state.

If they cannot be managed on iCloud.com either, we should investigate further before deleting anything.

Check Apple's explanation about lists that cannot be deleted

Apple states that a list cannot be deleted if a Smart List uses a condition such as “Card is member of” or “Card is not member of.”

You mentioned that Last Import is your only Smart List. Nevertheless, it is worth checking whether any other Smart Lists exist.

Apple's instructions are here:

Apple Support: Delete lists and Smart Lists in Contacts on Mac

Also check Apple's instructions for creating and editing Smart Lists:

Apple Support: Create and change Smart Lists in Contacts on Mac

However, a Smart List dependency would not necessarily explain why renaming is grayed out and dragging contacts fails. I would not assume this is the sole cause.

Test whether you can create and manage a new list

In Contacts on your Mac:

1. Choose File > New List.
2. Give the new list a temporary name.
3. Try dragging a contact into it.
4. Select the list and choose Edit > Rename List.
5. Try deleting the temporary list.

Apple's complete instructions for these operations are here:

Apple Support: Create and change lists in Contacts on Mac

If the new list works correctly, the problem may be specific to the original lists or the account containing them.

If the new list also cannot be renamed, edited, or deleted, that would suggest a broader problem with Contacts on your Mac or the account configuration.

Check your iCloud Contacts settings

If you use iCloud, open Apple menu > System Settings > your name > iCloud and check that Contacts is enabled.

Apple's instructions for setting up Contacts across devices are included here:

Apple Support: Add contacts from iCloud, Google, and more to Contacts on Mac

If Contacts is already enabled, I would restart the Mac and check for available macOS updates before attempting more extensive troubleshooting.

I would not turn iCloud Contacts off and back on, remove accounts, or delete any local contact databases until you have a backup.

Back up your contacts before cleaning up duplicates

Since you mentioned that the duplicates appeared after merging contacts from your phone and computer, I recommend making a backup before deleting any lists.

If the contacts are in iCloud, Apple explains how to export all contacts into a vCard file here:

Apple Support: Import, export, or print contacts on iCloud.com

Deleting a list is not the same as deleting the contacts themselves. However, it is important to establish which account contains the lists before cleaning up the duplicates.

I would not assume that you have accidentally changed a general Mac setting. The fact that renaming, deleting, and dragging contacts all fail on the Mac, while those operations work on your iPhone, makes it worth investigating the account and Contacts app before changing system settings.

One question would help narrow this down considerably:

In the sidebar of Contacts on your Mac, are the affected lists under iCloud, Google, Exchange, or On My Mac?

That information, together with whether you can rename a list on iCloud.com, should help identify the next troubleshooting step without risking your contacts.

From what you've described, this looks more like a problem with Contacts on your Mac or its iCloud syncing than a problem with the lists themselves.

A few things stand out:

• You can rename and delete lists on iCloud.com, so the lists themselves seem fine.
• The lists appear under All iCloud on your devices, not under Gmail.
• You have duplicate lists following the merge between your phone and Mac.
• A temporary list you created on the Mac initially allowed editing, but then stopped letting you add contacts, rename it, or delete it.
• You have no obvious Smart Lists that would explain why deletion is blocked.

Taken together, these symptoms suggest that Contacts on the Mac may not be handling iCloud list changes correctly. I'd test that before making any major changes.

Check the delete command in the menu

You've already tried pressing Delete, so let's see whether the menu behaves differently.

1. Open Contacts on your Mac.
2. Select one of the duplicate lists in the sidebar.
3. Control-click (right-click) the list and look for a delete option.
4. Check the Edit menu to see whether any list-related commands are available.

If you see Delete List, try it on a list you don't need. If the option is missing or disabled, that's a useful clue.

Apple also notes that a list can't be deleted if a Smart List references it through a “Card is member of” or “Card is not member of” condition. Since you've checked your Smart Lists already, this may not be the issue.

Test a brand-new list

The fact that your temporary list initially worked and then stopped accepting changes is particularly interesting.

Create another temporary list with a unique name, then see whether you can rename it, add a test contact, and delete it.

If those operations fail too, the problem is more likely to involve Contacts on the Mac or its iCloud connection than the individual lists.

Restart Contacts and check iCloud

Before changing any account settings, try the simple fixes first:

1. Quit Contacts completely using Command–Q.
2. Reopen it and try editing a list.
3. If the problem persists, restart your Mac.
4. Open Contacts >> Accounts and check that your iCloud account is signed in and that Contacts is enabled.

I wouldn't turn iCloud Contacts off and back on just yet. First, let's establish whether the Mac is failing to edit lists generally.

Use iCloud.com to clean up duplicates for now

Since list management works on iCloud.com, you can use the website to remove unwanted duplicate lists while we troubleshoot the Mac.

Deleting a list does not delete the contacts in it. The contacts remain in All Contacts.

I'd remove only the duplicates you're certain you don't need, then check whether those changes appear on the Mac. That will also help us determine whether iCloud changes are syncing properly.

My suspicion is that something is going wrong with Contacts on the Mac, particularly given that even a newly created list stopped behaving normally. But I'd hold off on rebuilding the Contacts database or resetting iCloud until we've narrowed it down.

The good news is that you can still manage your lists through iCloud.com, so you have a working alternative while investigating the Mac issue.

It's been a bug for me for generations of OS's. I fix it by closing the Contacts app, re-opening it and trying again. It usually works for a while until I have to close and open it again. I'm only on Sequoia so if your problems are caused by 27 then this might not work for you.

Can't find a way to edit my above post to add info to it, so here it is:

I also can't rename any list following the "highlight, then go to Edit>Rename list". The Rename list is grayed out.

I also cannot drag contacts into a list on my Mac.

I can delete lists, rename lists, and assign contacts to a list on my iPhone running iOS 27..

Is some general setting set wrong on my Mac?

Thanks for your reply Owl-53. Lots to check out.

I do have a gmail account in contacts, but all of these lists are under the "All iCloud" heading on all devices.

I did create a temporary list on the Mac that I was able to drag contacts into once. Then it wouldn't let me. I believe the rename was available too before the first drag & drop. Now it also won't let me delete that list either.

On the iCloud website I am able to add contacts to lists (in a different way), rename, and delete lists.

So I'm not sure where that leaves me.

Thanks Zurarczurx