Why does Office for Mac prompt me to close Google Chrome? Is that suspicious?

Question

Office for Mac 2008 just asked me whether I wanted to update. However, on continuing with the update, a Window popped up saying that I needed to close Chrome before the update could continue. I find this rather suspicious, since Office should not need to go anywhere near Chrome.

Any idea why there might be a legitimate reason for this, or alternatively, just what is Microsoft trying to sneak on to my computer?

I did look at the download details on Microsoft's website, but aside from the general guff about closing all open applications, it doesn't mention anything about Chrome or any browser plugins.

Answer 1

Because Office 2008 also updates Silverlight, this is totally safe, yet very uncomfortable; as usual, when it comes to Microsoft :-)

Answer 2

I just installed a Silverlight update with Chrome open on my Mac. The installer did not complain, and completed seamlessly. However, I have a Office 2011 update that still refuses to install until I close Chrome.

This is pretty strong evidence that Silverlight is not the culprit. According to this blog post, it's because the update fiddles with fonts. Still a terrible UX, though.

Answer 3

There are actually a few culprits, as explained here.

[T]he Office installer can modify/update the Microsoft Silverlight.plugin (which is installed in /Library/Internet Plug-Ins/), which Safari and Chrome could potentially be using.

It's primarily just a precaution against updating files which an application is actively using.

[EDIT]

After further investigation, it looks like it's actually the fact that the installer modifies the fonts in /Library/Fonts/Microsoft/ which is the motivation behind requiring that several apps not be running. The following is an excerpt from the XML Distribution script that's in the 16807Office 2011 14.3.5 Update.pkg installer package:

<choice id="fonts" selected="true" start_enabled="false"
  <start_selected="false" start_visible="false" title="fonts-title">
     <pkg-ref id="fonts">
         <must-close>
             <app id="com.apple.Safari"/>
             <app id="org.mozilla.firefox"/>
             <app id="com.google.Chrome"/>
             <app id="com.operasoftware.Opera"/>
             <app id="com.microsoft.Word"/>
             <app id="com.microsoft.Excel"/>
             <app id="com.microsoft.Query"/>
             <app id="com.microsoft.Powerpoint"/>
             <app id="com.microsoft.Outlook"/>
         </must-close>
     </pkg-ref> </choice>

[EDIT]

Another pair of potential culprits are

SharePointBrowserPlugin.plugin and SharePointWebKitPlugin.webplugin

They are installed by default with Office 2011 under /Library/Internet Plug-Ins. (Note: Silverlight was not an option to install with 2011).

So it's nothing to be suspicious about.