Skype for Business stops responding when receiving a toast notification of an IM or an incoming call in Citrix VDI environment


Assume that you use Microsoft Skype for Business 2016 or Skype for Business 15 (Lync 2013) in a Citrix VDI environment that has HDX RealTime Optimization Pack (RTOP) Connector installed. When you run one or more Lync SDK-based applications and receive a toast notification of an instant messaging (IM) or an incoming call, the client stops responding. 


Follow the steps in this section carefully. Serious problems might occur if you modify the registry incorrectly. Before you modify it, back up the registry for restoration in case problems occur.

To fix this issue. install one of the following updates:


Before you apply this update, make sure that you create a Group Policy Object (GPO) to add a new DWORD registry key EnableDelayPostingOfDeferredCOMEvents and set the value to 1 in the path:


Alternatively, you can enable this by creating a custom policy entry and add it to the client policy:

$x = New-CsClientPolicyEntry -Name "EnableDelayPostingOfDeferredCOMEvents" -Value "true"

Set-CsClientPolicy -Identity "<ClientPolicyName>" -PolicyEntry @{Add=$x}

Lync 2013 was upgraded to Skype for Business in April 2015.

Third-party information disclaimer

The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.

Need more help?

Expand your skills
Explore Training
Get new features first
Join Microsoft Insiders

Was this information helpful?

Thank you for your feedback!

Thank you for your feedback! It sounds like it might be helpful to connect you to one of our Office support agents.