Q: Mail not working with El Capitan

Yep...i am having the same issue too. Mail cannot connect to the servers!

I also have an app which is my cable TV app which used to allow streaming before ElCapitan, now, it keeps telling me that I need an internet connection.

I am connected but it seems like El Capitan is blocking connections to apps.

Even the app store can't connect!

So freaking annoying!

Totally destroyed my mail had to renter passwords for some accounts one account I deleted and reentered The most troublesome update I have had the misfortune to download

I downloaded El Capitan yesterday and now the Mail application abruptly closes whenever I try to open it.  Cannot even open Mail now.

I can open mail but when I try to change any settings in accounts mail freezes. It will not save he changes. Big problems with mail!

I have had two types of problems with Mail 9.0 which now seem to be resolved. Hopefully, this might be of some help to others who may have similar issues.

The first was that Mail seemed to be in an endless loop of downloading recent emails from an IMAP server. It would show the messages in the message overview column but would not display detail. They would then go away and come back. While this was going on I also was not able to send any messages. I was able to correct this behaviour by going to Mail->Preferences->Accounts and then for each account in the Advanced Tab I unchecked "Automatically detect and maintain account settings". I then quit Mail and when it restarted it appears to work fine. It loaded and displayed the previously problematic emails and messages which had not been sent were now sent. Subsequently, I was able to check "Automatically detect and maintain account settings" and things continue to work.

I then was able to notice a second issue. Although, this one was due to an enhancement to Mail which ran afoul of a workaround to a prior version's implementation for alias support. Specifically, there appears to now be explicit support for those who have multiple email addresses going to the same IMAP server. On prior versions of Mail one was able to have alias support by having comma separated email addresses in the single "Email Address field" of the Mail Account Information setting pane. In older versions you could only enter one variant of the Full Name associated with all of the comma separated addresses. So those that would use multiple addresses might choose to leave the Full Name blank.

With Mail 9 they seem to have implemented explicit support for email aliases. That is for a single account/imap server one can now have multiple pairs of addresses and full names. This is an enhancement. Although, I would have preferred that the migration would have converted my prior version's list of comma separated email addresses into individual alias entries. In my case I had over 50.

Additionally, the Email Address field in the Account information pane still has a hover display of "Enter one or more email addresses, separated by commas". Being able to enter multiple comma separated email addresses would now seem to be an error. It causes the send message to fail because it seems to be stringing multiple addresses together as if they were one email address and the SMTP server baulks at that.

I don't know what Mail was trying to do initially but unchecking "Automatically detect...", restarting Mail, and then checking it again seem to have gotten Mail working for me.

I am having exactly this issue as well - will not open at all. If I delete /Library/Mail/V3 then I will get the opening page which says 'Mail Upgrade' which stays visible for about 3 seconds then disappears, opens again and immediately closes. From there on in it simply crashes on startup.

Not sure if this will help but here is the first part of the error message

Process:               Mail [1369]

Path:                  /Applications/Mail.app/Contents/MacOS/Mail

Identifier:            com.apple.mail

Version:               9.0 (3094)

Build Info:            Mail-3094000000000000~1

Code Type:             X86-64 (Native)

Parent Process:        ??? [1]

Responsible:           Mail [1369]

User ID:               501

Date/Time:             2015-10-01 17:22:59.169 +0200

OS Version:            Mac OS X 10.11 (15A284)

Report Version:        11

Anonymous UUID:        DA18FC9E-4944-E2C5-B6A7-75FC02ECAB69

Time Awake Since Boot: 1800 seconds

System Integrity Protection: enabled

Crashed Thread:        0  Dispatch queue: com.apple.main-thread

Exception Type:        EXC_BAD_ACCESS (SIGSEGV)

Exception Codes:       KERN_INVALID_ADDRESS at 0x000000011511c5d0

Exception Note:        EXC_CORPSE_NOTIFY

VM Regions Near 0x11511c5d0:

    VM_ALLOCATE            000000011500d000-000000011500e000 [    4K] rw-/rwx SM=ALI 

-->

    __TEXT                 00000001151cc000-00000001151fb000 [  188K] r-x/rwx SM=COW  /Library/Mail/*/Sparkle.framework/Versions/A/Sparkle

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread

0   libobjc.A.dylib               0x00007fff9d4ffa49 search_method_list(method_list_t const*, objc_selector*) + 4

1   libobjc.A.dylib               0x00007fff9d4ffa26 getMethodNoSuper_nolock(objc_class*, objc_selector*) + 85

2   libobjc.A.dylib               0x00007fff9d501cba lookUpImpOrForward + 291

3   libobjc.A.dylib               0x00007fff9d500e11 objc_msgSend + 209

4   libc++abi.dylib               0x00007fff92a7ed6b __cxa_decrement_exception_refcount + 47

5   com.apple.mail                 0x000000010f183678 0x10efd1000 + 1779320

6   com.apple.mail                 0x000000010efd63b1 0x10efd1000 + 21425

7   com.apple.mail                 0x000000010efd53bc 0x10efd1000 + 17340

8   com.apple.CoreFoundation       0x00007fff8dae8a0c __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__ + 12

9   com.apple.CoreFoundation       0x00007fff8dae899f ___CFXRegistrationPost_block_invoke + 63

10  com.apple.CoreFoundation       0x00007fff8dae8917 _CFXRegistrationPost + 407

11  com.apple.CoreFoundation       0x00007fff8dae8682 ___CFXNotificationPost_block_invoke + 50

12  com.apple.CoreFoundation       0x00007fff8daa5442 -[_CFXNotificationRegistrar find:object:observer:enumerator:] + 1922

13  com.apple.CoreFoundation       0x00007fff8daa4695 _CFXNotificationPost + 693

14  com.apple.Foundation           0x00007fff9335e31a -[NSNotificationCenter postNotificationName:object:userInfo:] + 66

15  com.apple.AppKit               0x00007fff938ef045 -[NSApplication _postDidFinishNotification] + 297

16  com.apple.AppKit               0x00007fff938eedaf -[NSApplication _sendFinishLaunchingNotification] + 203

17  com.apple.AppKit               0x00007fff937a9f65 -[NSApplication(NSAppleEventHandling) _handleAEOpenEvent:] + 557

18  com.apple.AppKit               0x00007fff937a9a0f -[NSApplication(NSAppleEventHandling) _handleCoreEvent:withReplyEvent:] + 250

19  com.apple.Foundation           0x00007fff933acbbd -[NSAppleEventManager dispatchRawAppleEvent:withRawReply:handlerRefCon:] + 290

20  com.apple.Foundation           0x00007fff933aca37 _NSAppleEventManagerGenericHandler + 102

21  com.apple.AE                   0x00007fff9ac3c1b5 aeDispatchAppleEvent(AEDesc const*, AEDesc*, unsigned int, unsigned char*) + 531

22  com.apple.AE                   0x00007fff9ac3bf3c dispatchEventAndSendReply(AEDesc const*, AEDesc*) + 31

23  com.apple.AE                   0x00007fff9ac3be58 aeProcessAppleEvent + 288

24  com.apple.HIToolbox           0x00007fff96978ef5 AEProcessAppleEvent + 55

25  com.apple.AppKit               0x00007fff937a53d4 _DPSNextEvent + 2245

26  com.apple.AppKit               0x00007fff937a4369 -[NSApplication _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 454

27  com.apple.AppKit               0x00007fff93798ecc -[NSApplication run] + 682

28  com.apple.AppKit               0x00007fff93762162 NSApplicationMain + 1176

29  libdyld.dylib                 0x00007fff8df3a5ad start + 1

Very annoying!

Thats happening with me too..... Gee..... I really dont know what to do it!

I fix it!.... In my case I have 3 account´s..... so I just open it the control on email and unmark tia account from gmail.... and  it works for me

Experiencing the same issues with Mail. Could you post a step-by-step guide on how you reverted back using Time Machine? Not having Mail working properly has greatly affected my work today. Thanks so much.

My Earthlink account with not work with El Capitan. I followed one suggestion given below but no luck. I thought all was well because I have a Macbook with OS10.7.4, but there is no mail after Sept 28. Mail later than Sept 28 has been wiped

off my Earthlink on the web, also.