Lync Client won't Start


Had a weird issue the other day where as the Lync 2010 Client would not start. I had not received any updates, but it gets to signing in and then crashes.

I've removed it and removed the Microsoft Visual 2008 C++ that comes with it and reinstalled it but I still get the error:

Microsoft Lync 2010 has stopped working - A problem caused the program to stop working correctly....

When I debug it through Visual Studio, I get:

Unhandled exception at 0x771af482 (ntdll.dll) in communicator.exe: 0xC0000005: Access violation reading location 0x00000004.

In the Windows Event Log I get the following:

Faulting application name: Communicator.exe, version: 4.0.7577.0, time stamp: 0x4cc15778

Faulting module name: ntdll.dll, version: 6.1.7601.17514, time stamp: 0x4ce7b96e

Exception code: 0xc0000005

Fault offset: 0x0005f482

Faulting process id: 0x10fc

Faulting application start time: 0x01cd3415238cd8c2

Faulting application path: C:\Program Files\Microsoft Lync\Communicator.exe

Faulting module path: C:\Windows\SYSTEM32\ntdll.dll

Report Id: 8f958e12-a00b-11e1-8b46-a4badbeed198

Any ideas anyone?



May 17th, 2012 10:36am


Have you tried to log on another Windows account and see if s/he can start the Lync client?

Would you please delete the sip profile folder for this user on the computer and try again?The Sip folder path is like below


Hope this helps.



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May 18th, 2012 9:17am

I had the same issue this week with one of my users, I had to delete their profile and recreate it. I tried Sharon's tip but with no success.   Hope that helps
May 23rd, 2012 3:30pm

Hi Pete and Sharon,

Thanks for your tips.

I deleted the local communicator profile settings at 'C:\Users\username\AppData\Local\Microsoft\Communicator\' and Lync started straight away. Could almost kick myself for being such an easy fix!

Thanks again,


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May 28th, 2012 9:24am


Why should you kick yourself? If this software application was not such a piece of garbage, it would work correctly.

I just tried this "solution", and Lync 2010 STILL won't start. What a pile of trash. I wouldn't use it, except that it is mandated by my company. Talk about substandard software.

Off to reboot now (big surprise).

This software is garbage! You might want to find out who you paid to author it, and ask for your money back!!!

August 17th, 2012 2:08pm

I'm no MVP but you will need outlook and lync both closed for this!

Navigate to start/(search box)

Type certmgr.msg from the search bar

Under Certificates - Current User selecet personal / certificates and remove the certificate.

Navigate to the following C:\Users\username\AppData\Local\Microsoft\Communicator\   (Delete this communication folder)

Navigate to start/(search box)

Type in regedit

Do a find for communicator in the regestry - (hkey_current_user) / Software / Microsoft / Communicator / (Delete the communicator folder)

Now try sigining back into lync.

This works everytime I see the issue. I figured this out over an 1 year period after I got tired of deleting local profiles.

  • Proposed as answer by Vossige 8 minutes ago
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January 28th, 2013 6:59pm

See my comment above - I was in the same boat. Should resolve the issue
January 28th, 2013 7:01pm

I've tried this and it comes up as a fresh install, shows the welcome screen and asks to trust the server, what not.  It then logs in but after about a minute it will log back out and then hang again. 

Any ideas?

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October 11th, 2013 12:49am

Everything from AppData on do not exist on my computer. Any other ideas on how to fix this issue?
November 21st, 2013 6:15pm

The following worked for me:

  1. Killed the communicator.exe process from the Windows Task Manager
  2. Sarted Lync
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May 1st, 2014 11:10pm

have you tried syncing with internet time ?
August 21st, 2015 4:45pm

This worked for me! Thanx a lot!
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September 9th, 2015 3:35am

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