Excel Opens 2nd / Subsequent File from Explorer Slowly but within Excel Quickly

Question

In Excel on a Windows 10 machine, a client was having an issue in which Excel would open normally – including starting Excel by double-clicking a workbook file icon in Explorer. But, if Excel was already running, and she double-clicked a workbook in Explorer, it would take a long time / many seconds for the file to open. Yet, if she opened a file from within Excel, that too opened with normal speed.

I found the solution on Microsoft Learn at Excel slow to open second (or subsequent) file. I’m posting it here to make it available in the Microsoft Answers community.

Before fixing this, she had blank entries for registry keys HKEY_CLASSES_ROOT\Excel.Sheet.8\shell\Open\ddeexec and HKEY_CLASSES_ROOT\Excel.Sheet.12\shell\Open\ddeexec.

To fix this behavior, I changed both those values to the following:

[open("%1" /ou "%u")]

In searching for a solution, I found many suggestions that did not work. These included repairing Office and under Excel Options | Advanced disable (uncheck) Enable multi-threaded processing.

I’ll also mention Word did not display this same behavior.

I don’t fully understand all the parameters used with the open setting above and would love to learn more and have a discussion as to why this problem exists and why this solution works.

Answer 1

Hello adamAmiga0

Thanks for posting you concerns here.

After testing and query, the problem with slow opening of files in Excel when double-clicking on a workbook file in Explorer can occur due to an issue with the Dynamic Data Exchange (DDE) protocol. DDE is a mechanism for communication between different applications in Windows, which can be used for passing data from one application to another, or for updating data in real-time. In Excel, DDE can be used to open a file by passing the file name as a parameter. However, sometimes, the DDE information stored in the registry may become outdated or corrupted, causing issues with the opening of files. The solution you provided involves modifying the registry keys

HKEY_CLASSES_ROOT\Excel.Sheet.8\shell\Open\ddeexec

and

HKEY_CLASSES_ROOT\Excel.Sheet.12\shell\Open\ddeexec

Both values were corresponded to the DDE information for Excel workbook files. By setting the value of both keys to [open("%1" /ou "%u")], you are specifying that Excel should open the file using the DDE protocol, with the "/ou" option being used to update the DDE information for the file. This solution works because it resolves any issues with the DDE information stored in the registry, allowing Excel to open files more quickly when double-clicking on a workbook file in Explorer. Additionally, the fact that Word does not occurs the same behavior as Excel could be due to differences in the way DDE is implemented in the two applications.

Feel free to post back if there is anything unclear.

Chandy |Microsoft Community Support Specialist