Are you aware about the different client versions of Skype for Business? We have 2 possible versions available in the market: Click-to-Run and MSI. Click-to-Run is the client version that is available through Office 365 Portal. This is the version that downloads Office using a streaming system and Skype for Business is part of Office. Even if you don’t have the right to use Office using the portal because your signature does not offer Office as part of it, you’ll have Skype for Business Basic standalone available to download and this is a Click-to-Run version as well.
So where the issue starts? MSI versions of Office cannot coexist with Click-to-Run, this is not supported.
Office installed using Click-to-Run and Window Installer on same computer isn’t supported – It’s not possible to install them on the same machine anymore, but still sometimes you can get the issue yet.
The most common issue that this causes for Skype for Business specifically is Outlook crashing when trying to organize a Skype meeting, but there other issues that can occur and are known, crashes when trying to search for a user/contact is an example.
The most common situation where we see this happening is when customer has a version of Office already installed in his machine that he bought before and does not have Skype for Business included, and then an Office 365 subscription is bought and customer downloads Skype for Business Basic from Office 365 portal. As customer had installed Office before in his machine, that install is a MSI installation, but the Skype4B client download from the portal is Click-to-Run, as previous explained.
How to Identify if Office is MSI and Skype is Click-to-Run? (or vice-versa)
You can check for specific register keys in regedit. You can find more information on this article: https://msdn.microsoft.com/en-us/library/office/ff522355.aspx. This article talks about Outlook, but it is the same for Skype.
There is another way to identify, which is taking a look at some other regkeys in the following path:
This key can be a bit different (numbers can change, like for example, for Office 2013, it will start with 9015, but it will always be oFF1CE in the end) and you can have more than one – specially if you have Click-to-Run and MSI in the same machine, you’ll have more than one.
What you have to check is DisplayName:
If you see Click-to-Run on it, then you surely have Click-to-Run Office, and you can install Skype For Business Basic from the Office 365 portal. If you don’t have Click-to-Run in DisplayName, you have to install Skype for Business Basic MSI, which you can download here:
|Language||Lync Basic 2013 x32||Lync Basic 2013 x64||Skype for Business Basic x32||Skype for Business Basic x64|
|English (US)||Lync Basic 2013 (stand-alone)||Lync Basic 2013 (stand-alone)||Skype for Business Basic (stand-alone)||Skype for Business Basic (stand-alone)|