Before upgrading to El Capitan, you first want to clone your drive. While a Time Machine backup is a good option, if you need to revert to your previous OS X a clone is much easier and quicker than Time Machine. I suggest SuperDuper to clone your drive. SuperDuper is free to do an erase and clone. You can purchase to do schedule and smart backups. If you don’t have an external drive, check out this 3T Western Digital drive. (the 2T is often only a few dollars less). You can partition the drive and use it for clone and Time Machine.
If you are running Snow Leopard 10.6, Lion 10.7, Mountain Lion 10.8, I would suggest doing a clean install of El Capitan 10.11. If your version of OS X is 10.9 or higher, you can try upgrading El Capitan over your current install. You can always revert to the clone. Erase the internal drive and reinstall El Capitan if you find a clean install is warranted. (be sure to save the El Capitan installer. It can be found in Applications. It’s named “Install OS X El Capitan”. By default Apple deletes the installer after the install is finished.)
I’m going to focus on Apple Mail in this article. See 6 Steps to Prepare a Mac for the OS X El Capitan Update for other helpful tips before you upgrade.
Mail in 10.11 is imported from V2 to V3 folder. See Clean up Mail folder to free up space from your drive and Troubleshooting Apple Mail in OS X 10.11 El Capitan for more info. This import process has been troublesome for many users. I suggest you do a clean install of Mail to avoid any upgrade issues.
Before you upgrade to OS X 10.11 El Capitan.
In Mail, remove all your IMAP accounts and any Exchange accounts. Removing the account in Mail > Preferences will take you to System Preferences > Internet Accounts to remove. Simply uncheck Mail. When you add back in El Capitan all your settings will be remembered. You might need to add password again so be sure you have your passwords handy.
When you remove a POP account, the Inbox messages are removed from Mail. Be sure you export your data before removing a POP account. If the messages are no longer on the server or you do not have a backup of your Mail folder, you would loose the Inbox messages.
You can use Apple’s export as Apple Mailboxes or you can export with this third party option, Emailchemy. If you have lots of subfolders you’ll find that Emailchemy is worth every penny.
Export a folder in Mail
Under Mailbox in the Menu bar select Export Mailbox. You will need to do this for every folder and subfolder.
Use Emailchemy to export your folders.
Download Emailchemy. The demo will mask subject and sender fields in the converted email. Please try the demo before purchasing. This will save all the folders in Mail. Your folder sturcture will be saved. To purchase: $29.95
- Select Apple Mail to convert
- Select your Mail folder. By default Emailchemy will show the correct path.
- Select Convert
- Select your destination folder. Desktop is selected in this image.
- Save as MBOX file (standard mbox). This saves all your folders and subfolders. You keep your folder structure.
- You can delete the converted_email folder after importing or save to an external drive then delete.
After you have saved all your local mailboxes, in your User’s Library….
- Scroll down to Containers folder > delete the com.apple.mail folder
- Delete the Mail folder. Iif you do not have a Time Machine or clone backup of Mail simply rename to Mailxx. After you are satisfied with your El Capitan Mail upgrade, you can delete the Mailxx folder in your User’s Library.
- Restart and delete the Trash
Now you are ready to upgrade to El Capitan.
After the OS X 10.11 El Capitan install, go to System Preferences > Internet Accounts to add back your accounts. I suggest you add one account at a time. Let the account download fully before adding your other accounts. Some IMAP accounts need to have the Drafts, Trash and Junk folder set correctly.
Import the local “On My Mac” folders.
Under File select Import Malboxes…
If you used Mail to export, select Apple Mail.
If you used Emailchemy select the bottom option: Files in mbox format
Using either option you will find your folders under Import folder. Toggle open to view. You can move out of Import folder by dragging to the “On My Mac” header.
You can select to move the messages in default folders (Inbox, Drafts, Trash, Junk) under Import back to the top folders for your POP accounts. Note if you left messages in the Inbox on the server, you will have duplicates. Before adding the imported Inbox messages back, delete any newly download Inbox messages that are in your Imported Inbox
If you need personal assistance, you can contact me for support.