Because Microsoft Excel 2013 no longer allows saving workspaces with multiple views, you must use a workaround to open the same Excel document in more than one window or to display two different documents side-by-side. Double-clicking the document twice doesn't open two instances of Excel unless you modify the Windows Registry, and modifying the registry is a dangerous operation that can lead to various problems. If you prefer to avoid editing the registry, open a second window from within Excel or open a new Excel instance using a keyboard shortcut.
Open a Second Excel Window
Open your first Excel document in Excel and then open a second Excel instance by holding "Alt," right-clicking the "Excel" icon in the taskbar and then selecting "Excel (desktop)" from the context menu.
Release the "Alt" button when asked if you want to open a new instance of Excel and click "Yes" to open it. Open the second document in the second Excel window. Note that you can open the same document in both Excel windows.
Open a second Excel window within the same instance by launching Excel, opening the document, clicking "View" and then clicking "New Window" in the Window group. The same document is opened in both windows. Note the two windows are part of the same Excel instance; edits made in any of the windows are immediately reflected in the other window. Click "View Side by Side" to view different sections of the same document.
Open the Same Document by Double-clicking It
Press "Windows-X" to display the Power User menu, click "Run," type "regedit.exe" into the "Open" field and press "Enter" to open the Windows Registry Editor. Be careful -- changing or deleting the wrong keys or values may cause programs to malfunction and even crash the entire operating system.
Double-click the "HKEY_CLASSES_ROOT" key to expand it and then expand the "Excel.Sheet.12\shell\Open" key. Select the "command" key and locate the "(Default)" value in the right pane.
Double-click the "(Default)" value to edit it and then replace "/dde" with "/e" and append "%1" (including the quotation marks) to the string in the "Value data" field. The value data must look like this: "C:\Program Files\Microsoft Office\Office15\EXCEL.EXE" /e "%1". Click "OK" to save the changes.
Right-click the "command" value below the (Default) value and choose "Rename" from the context menu. Type a different name -- "command.old" for example -- and press "Enter" to rename the value.
Right-click the "ddeexec" key in the left pane and choose "Rename" from the context menu. Type a different name -- "ddeexec.old" for example -- and press "Enter" to rename the key.
Close the Registry Editor and then test the changes. Double-click the Excel document to open it in Excel. Return to the document and then double-click it again. When the File in Use dialog displays, click "Read Only." The document is opened as read-only in the second Excel window, so you can't edit it.
Use a separate instance to open a very large document that may take several minutes to open if you want to be able to continue working in Microsoft Excel.
You can open several Excel windows by using the "New Window" button, so you can view the same spreadsheet on several displays if necessary.
Instead of holding "Alt" and clicking "Excel (desktop)," you can launch a new instance from the Run dialog. Press "Windows-X" to open the Power User menu, click "Run," type "excel.exe /x" (without the quotes) into the "Open" field and press "Enter."
To ensure you don't break anything while editing the registry, right-click the "HKEY_CLASSES_ROOT\Excel.Sheet.12" value and choose "Export" from the context menu. Type a name for the backup into the "File name" field, select a folder and then click "Save."
The customized registry keys and values are replaced with original versions when you install Microsoft Office updates, so you need to repeat the procedure after each update.
If you open several windows using the "New Window" button, closing the last window closes the document. Make sure you save your work before closing the last window.