iMessage: An error occurred during activation. Try again.

This could be a complicated problem to solve, as there are many possible causes for it. Test after taking each of the following steps that you haven't already tried. Back up all data before making any changes.

Before proceeding, test on another network, if possible. That could be a public Wi-Fi hotspot, if your computer is portable, or a cellular network if you have a mobile device that can share its Internet connection. If you find that iMessage works on the other network, the problem is in your network or at your ISP, not in your computer.

Step 1

Check the status of the service. If the service is down, wait tor it to come back up. There may be a localized outage, even if the status indicator is green.

Step 2

Sign out of iMessage on all your Apple devices. Log out and log back in. Try again to sign in.

Step 3

Restart your router and your broadband device, if they're separate. You may have to skip this step if you don't control those devices.

Step 4

From the menu bar, select

 ▹ About This Mac

Below the "OS X" legend in the window that opens, the OS version appears. Click the version line twice to display the serial number. If the number is missing or invalid according to this web form, take the machine to an Apple Store or other authorized service center to have the problem corrected.

Step 5

Take the steps suggested in this support article. If you don't understand some of the steps or can't carry them out, ask for guidance.

Step 6

From the menu bar, select

 ▹ System Preferences... ▹ Network

If the preference pane is locked, click the lock icon in the lower left corner and enter your password to unlock it. Then click the Advanced button and select the Proxies tab. If the box marked SOCKS Proxy is checked, uncheck it. You don’t need to change any other settings in the window. Click OKand then Apply. Test.

The result may be that you can't connect to the Internet at all. Revert the change if that happens, or if iMessage still doesn't work. Remember that you must Apply any changes you make in the preference pane before they take effect.

Step 7

Select from the menu bar

 ▹ System Preferences… ▹ Flash Player ▹ Storage

and click

Block all sites from storing information on this computer

Close the preference pane.

Step 8

Make sure you know the ID and password you use with iMessage. Launch the Keychain Access application in any of the following ways:

☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)

☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.

☞ Open LaunchPad. Click Utilities, then Keychain Access in the icon grid.

Use the search box in the toolbar of the Keychain Access window to find and delete all items with "iMessage" or "com.apple.idms" in the name. Log out and log back in.

Step 9

Enable guest logins* and log in as Guest. Don't use the Safari-only “Guest User” login created by “Find My Mac.”

While logged in as Guest, you won’t have access to any of your personal files or settings. Applications will behave as if you were running them for the first time. Don’t be alarmed by this; it’s normal. If you need any passwords or other personal data in order to complete the test, memorize, print, or write them down before you begin.

Test while logged in as Guest. After testing, log out of the guest account and, in your own account, disable it if you wish. Any files you created in the guest account will be deleted automatically when you log out of it.

*Note: If you’ve activated “Find My Mac” or FileVault, then you can’t enable the Guest account. The “Guest User” login created by “Find My Mac” is not the same. Create a new account in which to test, and delete it, including its home folder, after testing.

If iMessage worked in the guest account, stop here and post your results.

Step 10

Start up in safe mode and log in to the account with the problem. You must hold down the shift key twice: once when you start up, and again when you log in.

Note: If FileVault is enabled, or if a firmware password is set, or if the startup volume is a Fusion Drive or a software RAID, you can’t do this. Ask for further instructions.

Safe mode is much slower to start and run than normal, with limited graphics performance, and some things won’t work at all, including sound outputand Wi-Fi on certain models. The next normal startup may also be somewhat slow.

The login screen appears even if you usually log in automatically. You must know your login password in order to log in. If you’ve forgotten the password, you will need to reset it before you begin.

Test while in safe mode. After testing, restart as usual (i.e., not in safe mode) and test again.

If iMessage worked in safe mode, but still doesn't work when you restart in "normal" mode, stop here and post your results.

Step 11

Triple-click anywhere in the line below on this page to select it:

/Library/Preferences/com.apple.apsd.plist

Right-click or control-click the highlighted line and select

Services ▹ Reveal in Finder (or just Reveal)

from the contextual menu.* A folder should open with an item selected. Move the selected item to the Trash. You may be prompted for your administrator login password. Restart the computer and empty the Trash.

*If you don't see the contextual menu item, copy the selected text to the Clipboard by pressing the key combination command-C. In the Finder, select

Go ▹ Go to Folder...

from the menu bar and paste into the box that opens by pressing command-V. You won't see what you pasted because a line break is included. Press return.

Step 12

Reset theNVRAM.

Step 13

Reinstall OS X.

Step 14

If none of the above steps resolves the issue, make a "Genius" appointment at an Apple Store, or contact Apple Support.

I'm done at Step 9. Guest logins work and I can access iMessage from there, primary account does not. Thoughts?

I solved it by opening activity monitor, force quitting identityservicesd and IMRemoteURLConnectionAgent.xpc. I then Relaunched finder and I was able to sign in. It is showing all contacts as not registered with iMessage though

I went through all suggestions - including reinstalling OS - and am still getting same error. I'm on Early 2009 Mac Pro.. MacBook Pro worked as soon as I updated, but have been unable to login in on Mac Pro for some reason. Any other insight would be appreciated.

I went through all steps except #10 (I use FileVault). I still can't login into Messages in my user account. I can login in Messages using another account I created for testing. I am not sure when the problem started. It could have started after I downgraded from Yosemite to Mavericks using a clone backup. I can't say for sure because I didn't use Messages for a while after this. Is there any hope in solving this problem?

Worked @ #9 what is next?

Thanks Linc,

I had done a migration from my MBP to a new iMac and iCloud was working but it would not let me connect to iMessages. Your suggestions worked for me. I believe step 8 (deleting "com.apple.idms" items from my keychain) finally did it. Thanks very much.

iMac (Retina 5K, 27-inch, Late 2015), OS X El Capitan (10.11.4)

Perfect. This worked.Thanks

Thank you so much... I completed all steps until after step 9 and it actually worked! I have had this problem for the last 7 months now and this was the first _real_ solution :-)

"I solved it by opening activity monitor, force quitting identityservicesd and IMRemoteURLConnectionAgent.xpc. I then Relaunched finder and I was able to sign in. It is showing all contacts as not registered with iMessage though"

This worked for me only with identityservicesd - I didn't have the IMremote. I also force quit iMessages from activity monitor and was able to sign in right away. My contacts remained registered.

This worked after trying eight million other things. You are the best person in the entire world.