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.

Hi J, Sorry for my delay. Since we cannot reproduce the behaviors you mentioned, we have done some tests from our side. One update is: The Group Policy settings may affected the instances of Excel. Please check if you can see the following key in the path in Registry (Windows key + R> Type in regedit and enter): Computer\HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Excel\DisableMergeInstance It should not exist there for normal users' environment. Best Regards, Gloria

Your latest reply, which I do not see here suggested an idea: MS has been flipping back and forth between MDI and SDI. Try a copy of Excel 2010. If I remember correctly it is MDI. Switching to SDI in 2013 was a cause for complaint. Granted, 2010 does not support all of the new features in 365/2019/2016, but it probably would be more comfortable for you work with that what ever other spreadsheet you are being forced to use.

Hi J, According to your description, opening files in different instances affects your copy paste in different files. I have tested from my side and when I do the copy paste in Excel files in different instances, the content can be pasted correctly. Where were these files saved/from/located? How can it affect the copy paste result for you? Best Regards, Gloria

Simply starting Excel in Safe Mode will disable all addins, like the 3 you mentioned. The point is, if you were to start Excel in Safe Mode and the problem went away, then you would know that one of them is probably the cause. So then you would do further investigation. But if starting in safe mode did not help, then there is no need to manually turn them off. Starting Windows in Safe mode is similar, but with Windows addins. I agree, with files that small, RAM is not likely to be an issue when just opening a few files. I agree, in this situation (small files), trying 64 bit is not likely to help. Just curious, why do you want them all in the same process? I can do simple copy / paste between 2 files open in 2 separate processes. Or are you doing something more "advanced" like using side-by-side view (which I found does need them both in the same process)? I'm guessing that opening a spreadsheet from Outlook may be the cause of separate processes. As a test, try attaching more than one spreadsheet to a single email and see if you can open them all in the same process. Then add more files to see if you run in to the same problem as before.

Hi Rohn007, Appreciate an MVP's insight, thanks for trying to help. Regarding the Outlook attachments - generally, I open my Outlook attachments for the sole purpose of comparing the contents with another file I have open in Excel at that point. I never need to edit the attachment, so it makes no difference to me where it's going to be saved. In fact saving the attachment in a folder before opening would be a bad practice for me in this case as it would simply be a waste of time, especially with the volumes I am currently going through (~30-50 per day). What would really make my job easier, would be if I could rely on Excel to always open my attachments in the same instance as the file I am comparing it with, so that I can copy&paste between workbooks if I need to and I don't need to update all the macros that do some of the comparing for me to account for accessing the attachment file in other Excel instances. As for the SafeMode - thank you for the explanation. As you can see, all that the support agent suggested at the time, was "Please start your PC in safe mode to see the result." and the hyperlink brings me to an article about Windows safe mode with no mention of Office safe mode. So if I was supposed to test the Office safe mode instead, I didn't know. I have one Acitve Addin that loads with my Excel - the MS Azure Information Protection. I also have a personal macro workbook in XLSTART folder. I deactivated the Azure addin now and removed the personal workbook from the startup folder - so no addins or macro files are loaded with Excel. And.... I'm seeing the same inconsistent results with multiple instances of Excel opening :( Regarding the RAM - one of my systems has 12, the other has 16 GB of RAM and as you can (almost) see in the gif files I shared earlier, my test Excel files are 11kB blank workbooks with one worksheet - I seriously doubt opening 10 of them at one time causes me to run out of RAM memory. The Excel attachments I open from Outlook are 100-150 kB in size so again, don't think that's too much for the system to handle. Also, to me, logically, if I have 1 Excel file open in my 1 Excel instance and then open another Excel file from Outlook attachment, surely opening a whole new instance of Excel for the attachment file vs. opening the attachment in the existing instance is going to require more RAM resources, would you agree with that? But hey, I'm all for finding the cause of the issue, so I will test it again tomorrow keeping an eye on the RAM usage. I am on 32 bit version (see the very first sentence in my initial post). Again, I doubt it's the RAM, so not sure how a 64-bit version would make a difference here. I can try installing it cause I'm all for thorough testing, but I've had it before and it kept crashing for me more than the 32-bit version. Most importantly though, the lack of Black office theme in 64-bit version is just a no-go for me. Thanks, J.

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

2019-01-11T05:42:56+00:00

Hi J,

Sorry for my delay.

Since we cannot reproduce the behaviors you mentioned, we have done some tests from our side.

One update is: The Group Policy settings may affected the instances of Excel.

Please check if you can see the following key in the path in Registry (Windows key + R> Type in regedit and enter):

Computer\HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Excel\DisableMergeInstance

It should not exist there for normal users' environment.

Best Regards,

Gloria
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Anonymous

2018-12-20T22:12:17+00:00

Your latest reply, which I do not see here suggested an idea:

MS has been flipping back and forth between MDI and SDI. Try a copy of Excel 2010. If I remember correctly it is MDI. Switching to SDI in 2013 was a cause for complaint. Granted, 2010 does not support all of the new features in 365/2019/2016, but it probably would be more comfortable for you work with that what ever other spreadsheet you are being forced to use.
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Anonymous

2018-12-19T21:30:34+00:00

Hi J,

According to your description, opening files in different instances affects your copy paste in different files.

I have tested from my side and when I do the copy paste in Excel files in different instances, the content can be pasted correctly.

Where were these files saved/from/located? How can it affect the copy paste result for you?

Best Regards,

Gloria
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Anonymous

2018-12-19T00:56:48+00:00

Simply starting Excel in Safe Mode will disable all addins, like the 3 you mentioned. The point is, if you were to start Excel in Safe Mode and the problem went away, then you would know that one of them is probably the cause. So then you would do further investigation. But if starting in safe mode did not help, then there is no need to manually turn them off.

Starting Windows in Safe mode is similar, but with Windows addins.

I agree, with files that small, RAM is not likely to be an issue when just opening a few files.

I agree, in this situation (small files), trying 64 bit is not likely to help.

Just curious, why do you want them all in the same process? I can do simple copy / paste between 2 files open in 2 separate processes. Or are you doing something more "advanced" like using side-by-side view (which I found does need them both in the same process)?

I'm guessing that opening a spreadsheet from Outlook may be the cause of separate processes. As a test, try attaching more than one spreadsheet to a single email and see if you can open them all in the same process. Then add more files to see if you run in to the same problem as before.
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Anonymous

2018-12-18T23:10:56+00:00

Hi Rohn007,

Appreciate an MVP's insight, thanks for trying to help.

Regarding the Outlook attachments - generally, I open my Outlook attachments for the sole purpose of comparing the contents with another file I have open in Excel at that point. I never need to edit the attachment, so it makes no difference to me where it's going to be saved. In fact saving the attachment in a folder before opening would be a bad practice for me in this case as it would simply be a waste of time, especially with the volumes I am currently going through (~30-50 per day). What would really make my job easier, would be if I could rely on Excel to always open my attachments in the same instance as the file I am comparing it with, so that I can copy&paste between workbooks if I need to and I don't need to update all the macros that do some of the comparing for me to account for accessing the attachment file in other Excel instances.

As for the SafeMode - thank you for the explanation. As you can see, all that the support agent suggested at the time, was "Please start your PC in safe mode to see the result." and the hyperlink brings me to an article about Windows safe mode with no mention of Office safe mode. So if I was supposed to test the Office safe mode instead, I didn't know.

I have one Acitve Addin that loads with my Excel - the MS Azure Information Protection. I also have a personal macro workbook in XLSTART folder. I deactivated the Azure addin now and removed the personal workbook from the startup folder - so no addins or macro files are loaded with Excel. And.... I'm seeing the same inconsistent results with multiple instances of Excel opening :(

Regarding the RAM - one of my systems has 12, the other has 16 GB of RAM and as you can (almost) see in the gif files I shared earlier, my test Excel files are 11kB blank workbooks with one worksheet - I seriously doubt opening 10 of them at one time causes me to run out of RAM memory. The Excel attachments I open from Outlook are 100-150 kB in size so again, don't think that's too much for the system to handle. Also, to me, logically, if I have 1 Excel file open in my 1 Excel instance and then open another Excel file from Outlook attachment, surely opening a whole new instance of Excel for the attachment file vs. opening the attachment in the existing instance is going to require more RAM resources, would you agree with that? But hey, I'm all for finding the cause of the issue, so I will test it again tomorrow keeping an eye on the RAM usage.

I am on 32 bit version (see the very first sentence in my initial post). Again, I doubt it's the RAM, so not sure how a 64-bit version would make a difference here. I can try installing it cause I'm all for thorough testing, but I've had it before and it kept crashing for me more than the 32-bit version. Most importantly though, the lack of Black office theme in 64-bit version is just a no-go for me.

Thanks,

J.
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