Hello, I have a problem with my Excel 2016 (16.0.10228.20051 32-bit): I have one Excel instance running. (N.B. - the " Ignore other applications that use Dynamic Data Exchange (DDE) " checkbox in Advanced Options is NOT checked.) What I need is - for all Excel files that I am about to open to open in my first and only Excel instanc e, always , and regardless of: how many files I open simultaneously, where the files are located (i.e. on local drive or on OneDrive so the system needs to download them before opening) and including when opening Excel files from other Office apps, i.e. Outlook attachments. The behavior that I've been seeing in Excel 2016 is, at best, inconsistent: When opening multiple additional files at once from disk (select multiple files/right-click/Open) - it opens the first n files in the first Excel instance, but then from n +1 file it starts opening them in a new instance. A variation of the above is when in my first and only Excel instance I have a workbook open in XLSTART folder. Then upon opening multiple files at once, when it reaches it's n +1 file and the new instance launches and tries to open the file in XLSTART folder again, but it is already open in the first instance, so the warning message saying " this file is already open " (or something like that) shows up and files n +2, n +3, n +4, etc. till the last one, will all try to open in a separate instance, each triggering the same warning message. I'd like to state at this point that this is not file specific, the file n +1 is usually a different file every time. Also, I am aware of the workaround (i.e. dragging files onto open Excel window) and I am using it - the above is to demonstrate the symptoms I've been experiencing. When generating Excel files by another application (call it AppX) - you might say that this is likely the AppX's issue - I have no means to verify this unfortunately, however, the randomness of the new instances launching in this case is similar to all other scenarios described here, so I doubt the cause is my AppX. Finally, when opening Excel files from Outlook email attachments - i.e. double-clicking an Excel attachment in Outlook's reading pane - it may open it in the first Excel instance, but may also decide to open it in a new one. From my testing, if the Excel's file previewer is disabled at that point (i.e. listed under Options/Add-Ins/Manage - Disabled Items) it will most likely open the attachment in a new instance. So that's my observations, hope it helps to shed some light on the issue. I know how to open files in a new instance if I want it. The problem is, it happens when I don't want it and in some cases, I don't seem to have any control over this. Thanks, J.

I am having the same issue with Office 365 ProPlus 32-bit Excel (Version 1803 Build 9126.2236 Click-to-Run). I often (but not always) want files opened in a single instance due to some of the reasons already described by other posters: ability to use Paste Special, linking between different files, copying large amounts of data, etc. The unpredictability of the Open behavior can get frustrating. Furthermore, since Microsoft removed the saved Workspace functionality (which would bypass the problem altogether), it is doubly annoying. I do miss Excel 2010. All that said: I am thinking that the issue may not lie entirely with Excel itself, but rather with File Explorer. In older version of Windows, it was possible to see, in Explorer Options, the exact command line that each right-click option runs (e.g. Open, New, Print, etc) for individual file extensions and their context. I am not seeing this option in Windows 10 (specifically Microsoft Windows 10 Enterprise [Version 10.0.16299.904]). However, in RegEdit, when I go to this registry entry: Computer\HKEY_CLASSES_ROOT.xlsx the Default value indicates the file type (presumably) is "Excel.Sheet.12". With this information in hand, I go to the following registry entry: Computer\HKEY_CLASSES_ROOT\Excel.Sheet.12\shell\Open I see this Default entry (path will vary based on where Office is installed): @C:\Program Files (x86)\Microsoft Office\Root\VFS\ProgramFilesCommonX86\Microsoft Shared\Office16\oregres.dll,-3 If I change this instead to (adjust path to wherever Office is installed): @C:\Program Files (x86)\Microsoft Office\root\Office16\EXCEL.EXE and click Open on multiple files (no instances of Excel running), initially in Task Manager it generates a separate instance of Excel for each file, but once the first instance opens, it "merges" (for lack of better word) all the selected files into a single instance. I've tried this with up to 15 (small) workbooks. Lamentably, there appears to be a shortfall with this workaround: if an instance of Excel is already running, and you Open the files as described above, they will open in a new instance - but at least it's a single new instance. Obviously, if the files have different extensions, you would need to do this for each one (e.g. xlsb, xlsm, xls). Also, I have not tested this extensively - only local files (not synced, not on Windows network), all opening in NOT protected mode and NOT read-only, not Outlook attachment, and not generated by any kind of external application such as an Export function in accounting software. These situation may warrant further testing. I realize this does not fully solve OP's issue, but hopefully it is a lead.

Buying a new version will rarely fix a "bug" like this. Before you spend the money, check to confirm that it really will, otherwise, if you are happy with the older version and it is still supported, save your money. Hint: you wouldn't be buying 2016 now, you would be buying 2019/365 (unless you buy 2016 from someone other than MS who has "old stock"). Rohn, Thank you for the reminder to not purchase software on the hope that the feature you need will be there. I did a quick Google search using "Does excel 2019 support MDI" and arrived at a link: https://answers.microsoft.com/en-us/msoffice/forum/msoffice\_excel-mso\_other-mso\_o365b/excel-2016-open-all-files-in-one-instance/3792d5ae-3d03-4251-9abd-eb81d64e8fde?page=4&rtAction=1547831502082 Alas, folks there are still grumbling about the lack of MDI support as recently as Jan. 16, 2019. Most of the comments are from power users who are very much connected to what's happening in Excel. You can go to the link above and register to receive email updates on the issue. So, my conclusion is NO MDI support in Excel 2019. Will be sticking with Excel 2010 for some time yet!

Thank you for the reply and letting me know that the forum is not MS supported. Good info to have. I did find an update and will see how that works next week. I have run into some interesting problems with Excel over the last twenty years but this one is very aggravating. Thanks again Rohn007.

Hi J, For the gif files you shared in the past, it seems that they are in synced environment and read-only files, could you please have a test in non-synced location and files not read-only? Thanks, Gloria

I am now wondering if I purchase office 2016 will it have the same problem? With all of their talent and money you still can't get a clear answer. Buying a new version will rarely fix a "bug" like this. Before you spend the money, check to confirm that it really will, otherwise, if you are happy with the older version and it is still supported, save your money. Hint: you wouldn't be buying 2016 now, you would be buying 2019/365 (unless you buy 2016 from someone other than MS who has "old stock"). The key to remember is that this forum is not "MS" supported. They pay for server and website maintenance ( not even a decimal place in their bottom line). They pay for a few, very few, MS staff to monitor the site. BUT MOST of the support here is provided by other users, people just like you (with a little more experience), who are NOT being paid by MS!

Excel 2016 - open all files in ONE instance

Anonymous

Hello,

I have a problem with my Excel 2016 (16.0.10228.20051 32-bit):

I have one Excel instance running. (N.B. - the "Ignore other applications that use Dynamic Data Exchange (DDE)" checkbox in Advanced Options is NOT checked.) What I need is - for all Excel files that I am about to open to open in my first and only Excel instanc e, always, and regardless of:

how many files I open simultaneously,
where the files are located (i.e. on local drive or on OneDrive so the system needs to download them before opening)

and including when opening Excel files from other Office apps, i.e. Outlook attachments.

The behavior that I've been seeing in Excel 2016 is, at best, inconsistent:

When opening multiple additional files at once from disk (select multiple files/right-click/Open) - it opens the first n files in the first Excel instance, but then from n+1 file it starts opening them in a new instance.
A variation of the above is when in my first and only Excel instance I have a workbook open in XLSTART folder. Then upon opening multiple files at once, when it reaches it's n+1 file and the new instance launches and tries to open the file in XLSTART folder again, but it is already open in the first instance, so the warning message saying "this file is already open" (or something like that) shows up and files n+2, n+3, n+4, etc. till the last one, will all try to open in a separate instance, each triggering the same warning message.

I'd like to state at this point that this is not file specific, the file n+1 is usually a different file every time.

Also, I am aware of the workaround (i.e. dragging files onto open Excel window) and I am using it - the above is to demonstrate the symptoms I've been experiencing.

When generating Excel files by another application (call it AppX) - you might say that this is likely the AppX's issue - I have no means to verify this unfortunately, however, the randomness of the new instances launching in this case is similar to all other scenarios described here, so I doubt the cause is my AppX.
Finally, when opening Excel files from Outlook email attachments - i.e. double-clicking an Excel attachment in Outlook's reading pane - it may open it in the first Excel instance, but may also decide to open it in a new one. From my testing, if the Excel's file previewer is disabled at that point (i.e. listed under Options/Add-Ins/Manage - Disabled Items) it will most likely open the attachment in a new instance.

So that's my observations, hope it helps to shed some light on the issue. I know how to open files in a new instance if I want it. The problem is, it happens when I don't want it and in some cases, I don't seem to have any control over this.

Thanks,

Locked Question. This question was migrated from the Microsoft Support Community. You can vote on whether it's helpful, but you can't add comments or replies or follow the question.

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47 answers

Anonymous

2019-01-24T19:04:17+00:00

I am having the same issue with Office 365 ProPlus 32-bit Excel (Version 1803 Build 9126.2236 Click-to-Run). I often (but not always) want files opened in a single instance due to some of the reasons already described by other posters: ability to use Paste Special, linking between different files, copying large amounts of data, etc. The unpredictability of the Open behavior can get frustrating. Furthermore, since Microsoft removed the saved Workspace functionality (which would bypass the problem altogether), it is doubly annoying. I do miss Excel 2010.

All that said: I am thinking that the issue may not lie entirely with Excel itself, but rather with File Explorer. In older version of Windows, it was possible to see, in Explorer Options, the exact command line that each right-click option runs (e.g. Open, New, Print, etc) for individual file extensions and their context. I am not seeing this option in Windows 10 (specifically Microsoft Windows 10 Enterprise [Version 10.0.16299.904]).

However, in RegEdit, when I go to this registry entry:

Computer\HKEY_CLASSES_ROOT.xlsx

the Default value indicates the file type (presumably) is "Excel.Sheet.12". With this information in hand, I go to the following registry entry:

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

I see this Default entry (path will vary based on where Office is installed):

@C:\Program Files (x86)\Microsoft Office\Root\VFS\ProgramFilesCommonX86\Microsoft Shared\Office16\oregres.dll,-3

If I change this instead to (adjust path to wherever Office is installed):

@C:\Program Files (x86)\Microsoft Office\root\Office16\EXCEL.EXE

and click Open on multiple files (no instances of Excel running), initially in Task Manager it generates a separate instance of Excel for each file, but once the first instance opens, it "merges" (for lack of better word) all the selected files into a single instance. I've tried this with up to 15 (small) workbooks.

Lamentably, there appears to be a shortfall with this workaround: if an instance of Excel is already running, and you Open the files as described above, they will open in a new instance - but at least it's a single new instance.

Obviously, if the files have different extensions, you would need to do this for each one (e.g. xlsb, xlsm, xls). Also, I have not tested this extensively - only local files (not synced, not on Windows network), all opening in NOT protected mode and NOT read-only, not Outlook attachment, and not generated by any kind of external application such as an Export function in accounting software. These situation may warrant further testing.

I realize this does not fully solve OP's issue, but hopefully it is a lead.
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Anonymous

2019-01-18T17:33:31+00:00

Buying a new version will rarely fix a "bug" like this. Before you spend the money, check to confirm that it really will, otherwise, if you are happy with the older version and it is still supported, save your money.

Hint: you wouldn't be buying 2016 now, you would be buying 2019/365 (unless you buy 2016 from someone other than MS who has "old stock").

Rohn,

Thank you for the reminder to not purchase software on the hope that the feature you need will be there. I did a quick Google search using "Does excel 2019 support MDI" and arrived at a link:

https://answers.microsoft.com/en-us/msoffice/forum/msoffice\_excel-mso\_other-mso\_o365b/excel-2016-open-all-files-in-one-instance/3792d5ae-3d03-4251-9abd-eb81d64e8fde?page=4&rtAction=1547831502082

Alas, folks there are still grumbling about the lack of MDI support as recently as Jan. 16, 2019. Most of the comments are from power users who are very much connected to what's happening in Excel. You can go to the link above and register to receive email updates on the issue. So, my conclusion is NO MDI support in Excel 2019. Will be sticking with Excel 2010 for some time yet!
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Anonymous

2019-01-17T15:01:23+00:00

Thank you for the reply and letting me know that the forum is not MS supported. Good info to have. I did find an update and will see how that works next week. I have run into some interesting problems with Excel over the last twenty years but this one is very aggravating. Thanks again Rohn007.
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Anonymous

2019-01-17T07:46:02+00:00

Hi J,

For the gif files you shared in the past, it seems that they are in synced environment and read-only files, could you please have a test in non-synced location and files not read-only?

Thanks,

Gloria
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Anonymous

2019-01-16T16:36:21+00:00

I am now wondering if I purchase office 2016 will it have the same problem?

With all of their talent and money you still can't get a clear answer.

Buying a new version will rarely fix a "bug" like this. Before you spend the money, check to confirm that it really will, otherwise, if you are happy with the older version and it is still supported, save your money.

Hint: you wouldn't be buying 2016 now, you would be buying 2019/365 (unless you buy 2016 from someone other than MS who has "old stock").

The key to remember is that this forum is not "MS" supported. They pay for server and website maintenance ( not even a decimal place in their bottom line). They pay for a few, very few, MS staff to monitor the site. BUT MOST of the support here is provided by other users, people just like you (with a little more experience), who are NOT being paid by MS!
Was this answer helpful?

1 person found this answer helpful.

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