Hope this is the right place to post that. 

I have installed the latest version of Lync for 2011 on my MBA running yosemite. It was previously installed and working fine when I was working for my previous company. Since then, I have completely reinstalled my MBA with new OS and moved the users home folder to a different location (another partition).

Now when I try to start Lync it crashes immediatly:

Error Signature:
Exception: EXC_BAD_ACCESS
Date/Time: 2015-04-13 20:53:34 +0000
Application Name: Microsoft Lync
Application Bundle ID: com.microsoft.Lync
Application Signature: UCCP
Application Version: 14.0.11.150304
Crashed Module Name: libcorecrypto.dylib
Crashed Module Version: unknown
Crashed Module Offset: 0x00035a4a
Blame Module Name: Microsoft Lync
Blame Module Version: 14.0.11.150304
Blame Module Offset: 0x0000725a
Application LCID: 1033
Extra app info: Reg=English Loc=0x0409
Crashed thread: 0

I have tried reinstalling it and did a clean uninstall using the following guide:

https://support.microsoft.com/en-us/kb/2691870

But the error returns for the new installation. 

The weird thing is that when the new installation, after clearing/deleting all the old files, I see a new MicrosoftLyncRegistrationDB.<GUID>.plist file created in the /Library/Prefrences/ByHost folder and the content of the file is populated with data from the my old working place?!

It appears that even thought I have cleared/deleted all the files according to the KB something is still pointing my client to use the old settings and that's why it crashes.

Can anyone suggest any other location to look for Lync setting files other than what is suggested in the KB?

Hi kyury,

Please try to uninstall it again by following the steps below.

1.  Drag the Lync application to the Trash.

2.  Remove the following files and folders.

/Users/<username>/Library/Preferences/com.microsoft.Lync.plist

/Users/<username>/Library/Preferences/ByHost/MicrosoftLyncRegistrationDB.xxxx.plist

/Users/<username>/Library/Logs/Microsoft-Lync-x.log (this file is present only if you turned on Lync Logging)

/Users/<username>/Library/Logs/Microsoft-Lync.log

/Users/<username>/Library/Caches/com.microsoft.Lync

/Users/<username>/Documents/Microsoft User Data/Microsoft Lync Data/

/Users/<username>/Documents/Microsoft User Data/Microsoft Lync History/

/Library/Internet Plug-Ins/MeetingJoinPlugin.plugin

3.  Delete all keychains that start with OC__KeyContainer.

4. Delete all e-mail address certificates.

5.  Empty the Trash.

Best regards,

Eric

Hi Eric, thank you very much for your reply.

I believe that your suggestion is pretty much as what is in the official Microsoft guide and I have tired with no success.

Non the less, while performing what you have suggested one more time, I have discovered the what I believe was the source of my problem. For some reason, and I'm no expert to MAC/OSX I have at least 2 'Library' folders. I believe it is because I have moved my users profile after the initial install of Yossemite. While cleaning the 'Library' folder, according to the official guide and what you have suggested here, I was cleaning the Library which is accessible through the 'Go' menu in the Finder. I then found another 'Library' folder located in the System drive. There was a file there called '/Library/Internet Plug-Ins/MeetingJoinPlugin.plugin' - so basically I had 2 of those files, one in my Library and another in the Library located in the System drive. 

Anyways, deleting that file solved my issue!

Thank you!