Q: Why does Mail crash when trying to reply to an email when Safari is also open

I have exactly the same problem. Started with installing 10.11.1. When Safari has an open window, and I reply to a mail by NOT opening the mail but just SELECTING the mail and hit reply, Mail crashes. When I open an email and then hit reply, no crash. When Safari is running but the Safari window is minimized, everything works normally. So far nobody has been able to provide a solution to my problem. Have sent 20+ crash reports to Apple. No response.

Testing in a new User will quickly tell you if the problem is system wide or if it's your User's folder that contains the problem.

CREATE A NEW USER

Go to System Preferences --> Create a New User in Users & Groups.

Switch to the New User by logging out under the Apple in the Menu bar.

Log into the test User.

You can skip signing in with Apple ID unless you want to test iCloud email.

Does the problem go away?

If yes, download EtreCheck and paste results here for help troubleshooting.

http://www.etresoft.com/etrecheck

I created a new user and the problem went away. But what do I do with my existing account? Migrating everything over to the new account amount to reinstalling the OS. I did do a reinstall already but not a clean reinstall.

I received your reply via email, but Safari is not showing your post so I can reply directly.

I created a new user and the problem went away. But what do I do with my existing account? Migrating everything over to the new account amount to reinstalling the OS. I did do a reinstall already but not a clean reinstall.

The new User tells us there is a problem in your User's folder.  See this post for help moving your data over to the new User.

Move your data to a new User or a new Mavericks partition **

Some times moving to a new User can be the better option, however it's worth trying to find the culprit(s) in your User's folder. The Etrecheck report would help.

Test after each step.

1) Start by disabling all extensions in Safari.

2) With Safari quit.

1.  Rename Safari folder in your User's Library to SafariXXX.

2.  Open Safari and it will open with a new blank profile.

3.  If this fails to fix, you can remove the new Safari folder and rename the original by removing the xxxs.

2) Validate your fonts.

How to use Font Book to validate fonts

  1. Open Font Book in your Applications folder.

  2. Select All Fonts.

  3. Now click in the list of fonts and select all (Edit > Select All).

  4. Under File in the Menu bar, select Validate Fonts.

  5. Duplicate fonts will be marked with either the yellow badge or a black dot.

  6. Select to remove or delete duplicates.*

  7. Delete font caches

  8. Restart your computer

* Step 6 – remove or delete duplicates is where the tricky part comes in. You can select to let Font Book disable or remove duplicates, but I’ve found that it removes the one you have not been using rather than selecting the best option. See Font Management in OS X, by Kurt Lang, for more info on fonts.

http://www.jklstudios.com/misc/osxfonts.html

See Kurt Lang's directions here to remove font caches

https://discussions.apple.com/message/26188553#26188553

** (Fair disclosure: Needhelp4Mac is my site. I may receive some form of compensation, financial or otherwise, from links on my site.)

Doesn't fix the problem.

It might be easier to move to a new User or use a different browser. I'm not sure an update will fix this issue. You can wait until OS X 10.11.2 comes out then decide what to do.

I have a similar issue on Mail crashing on reply or forward. I found it is related to Trusteer Rapport being active on a Safari page. I do not know what apps are shared between the two, but changing the web page to another without Trusteer Rapport active solved the problem.

You are correct. After turning off Trusteer Rapport, the problem went away. Still a bug in OS X though. How can this happen? Aren't apps supposed to run in their sandboxes without interfering with one another?

andreasfrommenlo park wrote:

 

... After turning off Trusteer Rapport, the problem went away. Still a bug in OS X though. How can this happen? Aren't apps supposed to run in their sandboxes without interfering with one another?

Trusteer "Rapport", like all similarly ill-conceived "anti-virus" garbage, does not run in a "sandbox". It is a modification to OS X that will result in random crashes and generally unreliable behavior. It will achieve the ultimate in computer security, which is to render your own computer effectively unusable.

The bug is not in OS X. The bug is "Rapport". Get rid of it. Do not install anything like it ever again.

I have the same issue with Trusteer.  If Safari is open and Trusteer is running, when Mail is open and Forward or Reply buttons selected, the Mail app crashes.  If Safari is not open or Trusteer is turned off while Safari is open, no problem.

Amen!  Thanks, Yoda :>)

OMGGGGGG, Thank you, I've been pulling the hair out of my head and I'm bald to try and understand why this was happening.

Now I hope this solves my problem of my iMac 27" mid 2011 from crashing because it got a breeze from who knows where and also, from keeping my computer from running a lot hotter than normal.

Thank for this post!!!!