Latest Office update (October 2016) and eXtyles

On October 11, 2016, Microsoft released the latest security and non-security update for Office. Unfortunately, eXtyles users have reported that Word hangs, crashes, or completely disables eXtyles immediately after this update is installed. In the 17 years that we have provided eXtyles as a workflow solution, this is the first time Microsoft has issued a patch that has had this kind of impact.

Update (November 8, 2016):

Microsoft has published a support article detailing the issue introduced by the Office 2016 Click-to-Run update released this month: VBA forms are not working as expected. In this article, Microsoft describes the potential effects of this update:

In some cases, your Office app may stop responding when you attempt to open a macro-enabled file containing form controls

As of November 2, Microsoft has released a fix for this bug in their latest update, Version 1609 (7369.2054):

On November 2, 2016, we released an update, Version 1609 (7369.2054), which fixes the set of issues related to VBA form controls. To install the update, click File > Account > Update Options > Update Now.

We have updated the Workarounds and Solutions section at the bottom of this article to reflect this fix.


The eXtyles engineering team has isolated the problem to an updated Microsoft Office component, FM20.DLL.

eXtyles uses a Microsoft user interface control called a List Box to display the list of files available for comparison in the Compare to Baseline dialog. The latest version of the Microsoft Office component FM20.DLL introduced a bug that causes Word to hang when loading a Visual Basic template that includes this List Box control. As a result, when Word loads eXtyles on application startup, Word hangs when it encounters this control in the eXtyles application.

Interestingly, with the Office Update installed, there are two copies of the FM20.DLL file. The copies, when running 32-bit Windows, are:

  1. C:\Windows\System32, version 12.0.6723.5000 with a digital signature applied on June 16, 2015
  2. C:\Program Files\Microsoft Office\root\VFS\SystemX86, version 16.0.7329.1017 with a digital signature applied on October 8, 2016

It’s the newer DLL in the Office directory that is at fault.

This problem of conflicting components has been dubbed “DLL Hell.” While many solutions have been proposed over the years, Microsoft has never fully resolved the problem. In the case of eXtyles, the newer version of FM20.DLL is located in the Office directory structure and, because eXtyles is an Office add-in, Word gives the newer version precedence over the older version that is found in the system directory. Short of copying the older version into the Office directory structure, there is not much we can do unless we simply stop using Microsoft’s List Box in eXtyles. This is a work-around we will investigate if Microsoft is unable to quickly fix the problem.


As of November 2, 2016, Microsoft has released a fix for this bug in their latest update, Version 1609 (7369.2054). To install this update, click File > Account > Update Options > Update Now


Note: Microsoft has resolved this issue in their latest Office update as of November 2. Please refer to the above “Solution” section to resolve the problem. The following workarounds have been retained for historical record.

Inera has reported the problem to Microsoft and stressed to Microsoft that the problem is quite urgent. We understand from Microsoft that the planned November 8 Office update will resolve this bug.

In the interim, we recommend that you do not install the latest Office update. If you have not already done so, disable Automatic Updates from Microsoft until the next update has been released.

Unfortunately, once installed, this update cannot be uninstalled. If you have already installed this update and are encountering problems, we recommend the following workarounds:

Revert to an earlier “Click-to-Run” update

Please refer to Microsoft’s support article regarding this update for instructions on reverting to an earlier version of Office.

Uninstall Skype for Business

If you are running Office 2010 or Office 2013, try uninstalling Skype for Business. We believe that the problematic Office component was introduced by an update to Office’s version of Skype, and uninstalling Skype for Business “backs out” the offensive file.

Swap FM20.DLL

WARNING: This option carries some risk, but if you follow these instructions carefully, you can back out this fix.

On 32-bit versions of Windows:

  • Copy the file C:\Program Files\Microsoft Office\root\VFS\SystemX86\FM20.DLL to a safe location
  • Copy the file C:\Windows\System32\FM20.DLL to C:\Program Files\Microsoft Office\root\VFS\SystemX86\, overwriting the newer copy of this file with the older file

On 64-bit versions of Windows

  • Copy the file C:\Program Files (x86)\Microsoft Office\root\VFS\SystemX86\FM20.DLL to a safe location
  • Copy the file C:\Windows\SysWOW64\FM20.DLL to C:\Program Files (x86)\Microsoft Office\root\VFS\SystemX86\, overwriting the newer copy of this file with the older file

Based on our testing, we believe this change should be safe for Word, Outlook, and Excel. We do not know if this change will cause problems for Skype for Business.

Note: after applying the above workaround, you may see the following message: “compile error in hidden module o12_eXtylesRibbon”. Please follow the instructions in this FAQ article to re-enable eXtyles.