After a recent security update for our XP workstations, a couple complaints came in where user’s were having difficulty opening Microsoft Office files across the network. In some cases, the file would open, but only after a delay of a few minutes. In other cases, the file would not open at all, causing the Office application (Word, Excel) to become unresponsive and hung up. The files were not ridiculously large, and opening the same files locally did not present a problem. Identifying the cause was a simple matter of turning to Process Explorer and examining the stack of the working program thread:

You can see the stack growing with a couple dozen calls to some component named GKExcel.dll. Turning on the Lower Pane to view DLLs (View > Lower Pane View > DLLs), I can see it is described as Microsoft Component, but the description is too generic to make out the purpose:

However, one of the functions may allude to what its purpose is and how it got here. Searching FValidateExcelFile takes me to this MS KB article Excel workbooks may open slowly over the network:

After you install MS11-021 and the Office File Validation (OFV) Add-in for Microsoft Office 2003 (KB 2501584), workbooks stored in a network location open more slowly over the network in Excel 2003 than they did without the OFV installed. The decrease in performance depends on the size of the workbook and bandwidth of the network, and in some scenarios, can seem to cause Excel to crash.

The issue is not specific to Excel, however. Word files were taking several minutes to open as well. Resolving is a simple matter of uninstalling the Microsoft Office File Validation Add-in or modifying the registry to make an exception for the application opening the file. To do this:

• Go to HKCU\Software\Policies\Microsoft\Office\<ver>\<application>\Security.
• Create a new key called FileValidation
• Create a DWORD value called EnableOnLoad with a value of 0

If uninstalling across the enterprise, then: msiexec / x {90140000-2005-0000-0000-0000000FF1CE} / quiet.