This will explain how to fix Windows so that you have the choice of opening multiple Excel workbook files in a single
instance, or separately. I wrote these instructions for Windows XP and Excel 2003, because they are the simplest to
describe, but the concepts should also apply to later releases.
The main advantage of being able to run multiple
files in one instance is that it enables all workbooks to access macros from any other workbook. This is extremely useful
for automating tasks that require exchanging information between workbooks.
However, if you open multiple files in
multiple instances of Excel, then all workbooks run independently. They can then run identical macros in each without
interference, or easily be displayed in separate windows on multiple monitors.
There is one Excel setting that
might have been changed manually that could fix this without having to do all of the other steps below, so try this first.
Step 1 - Excel PreferencesIn Excel, go to:Tools, Options, General tabThe “Ignore other applications” preference is
supposed to be able to control your choice of opening Excel in a single instance, or in separate instances.
Check “Ignore other applications” for separate instances.Uncheck “Ignore other applications” for a single instance.To test to
see if it’s fixed, first close all Excel files, and then open two files via Windows Explorer. If Excel is now working the
way you want, then you’re done. Yay!
If it’s still not working, you should know that it’s unlikely you did
something to cause Excel’s behavior to change. Windows Updates are usually the cause of this capability being reset. Here’s
how to fix it.
Step 2 - Repair the Windows RegistryGo to: Start, Run, and enter “excel.exe /unregserver” (without
the quotes.) This runs instantly and gives no visual feedback.
Then go to:Start, Run, and enter “excel.exe /regserver” (without the quotes.)This takes a minute or so to run. There will be
a couple of popup windows, and there will be no visible change when it’s done. However, you have just un-registered and
re-registered Excel, so your system will be back to a clean starting point.
Step 3 - Repair the Windows startup
commandsIn Windows Explorer go to: Tools, Folder Options, File Types tab, select XLS, Advanced, select Open, Edit (Tip: To
quickly select XLS in the long File Types list, just type XLS.)At this point you should be looking at a dialog box titled
“Editing action for type: Microsoft Excel Worksheet”. Here is a list of what these fields should be at this point in the
process:Action: &OpenApplication used to perform action:"C:Program FilesMicrosoft OfficeOFFICE11EXCEL.EXE" /e %1 Use DDE:
checked DDE Message: [open("%1")] Application: EXCEL DDE Application Not Running: blank Topic: SystemYou will need to
repair two fields:1. Add quotes to the “%1” argument in the fieldApplication used to perform action:"C:Program FilesMicrosoft
OfficeOFFICE11EXCEL.EXE" /e “%1”This fixes the problem where Windows can’t find the file because of spaces in the pathname.2.
Add a comment in the fieldDDE Application Not Running: [do nothing if Excel is not already running]Any text can be entered
in the square brackets. This prevents Windows from opening Excel twice the first time it’s invoked. When there is a comment
in this field, Windows will ONLY run the “DDE Message” action the first time Excel is opened.
At this point, you
should be able to use Step 1 above to set the “Ignore other applications” preference to work the way you want it to.
One last note: If you run multiple files in one instance, but want to be able to Alt-Tab between them,In Excel, go
toTools, Options, View tabCheck the “Windows in Taskbar” preference. This will display each file separately in your Windows
Taskbar, and you will be able to quickly Alt-Tab between them.