open one instance of Excel by default or force one instance ever for xlsx files in all user accounts

[ripmurdock]

Hello,

I hope someone can figure this out. I've tried every solution in every thread I can find.

I'm running Windows 10 and Office 2007.

I'm trying to stop a new behavior by Excel. All of a sudden, every time I open an xlsx file from Windows Explorer while logged in through my primary user account, a new instance of Excel is opened.

When I open an xls file from Windows Explorer, Excel exhibits the conventional behavior. I've also checked each of the previously created user accounts on the PC, and those accounts continue to successfully open xlsx files from Windows Explorer in an existing instance of Excel, if one is open.

I've tried these proposed solutions:
I've downloaded FileTypesMan. The DDE Message value already read "[open("%1")]" for both xlsx and xls files. I changed them and changed them back again, just to be sure.
I've changed the default application for both xlsx and xls files to Notepad and changed them back again.
This Excel option was already unchecked, but I checked it, restarted Excel, and unchecked it again for good measure: "Ignore other applications that use Dynamic Data Exchange (DDE)."
I've unchecked and checked "Show all windows in the Taskbar"

I'd be open to a solution that stops all Office applications from ever opening multiple instances. I don't have a use case for multiple instances of Office applications.

Thanks for your help.

 

[Logit]

I haven't experienced this issue. Have you tried reloading Excel ?

 

[ripmurdock]

I have run the Office repair. I'm trying to avoid uninstalling and reinstalling Office because the set-up is onerous given the extensive VBA macros I use to automate Excel, Word, and Outlook. I also use a couple of Excel add-ins that will require that I repurchase the add-ins to reinstall them. And every time I set up gmail as an Outlook mail server, google changes the security requirements. The last time I went through the authentication process, the authentication process did not work as described in google's instructions, so I'm not sure I will be able to navigate google's authentication system again. I use multiple gmail accounts as Outlook mail servers.

Even if I undertake the uninstall and reinstall of Office, I will probably have to do it all over again next time this happens to my Office installation.

Most of the posts regarding Windows Explorer opening a new instance of Excel for every xlsx file point to either a Windows Update or an Excel crash as the precipitating event. A couple of posts say that Excel continues to work as designed in other user accounts. I didn't see any posts that tested whether the aberrant behavior extended to xls files, which in my case it does not.

I have identified the SID codes for each account in regedit and many entries that include both xlsx and the specific SID codes. My guess is one of these entries must be different for the user account that always opens a new instance of Excel from Windows Explorer for xlsx files, but not xls files.

If there is a registry entry that can stop any Office application from opening multiple instances, that would be an acceptable solution for me.

Thanks for your help.

 

[Logit]

There appears to be more Microsoft Programmers and those who have been certified in MS Curriculums located on this Forum : Newest 'vba+excel' Questions

You'll need to register before posting. And of course, you'll need to include links on this Forum and StackOverflow for your posts on both Forums.

I believe someone there might be more knowledgeable to assist.