CAUSE
This behavior occurs when you use the Save As command on the File menu to
save the file, and you change either the file format or the filename. If
you change the file format, the Multi-User Editing feature is not turned on
in the new file, because you can only share a Microsoft Excel Workbook
file.
For additional information, please see the following article in the
Microsoft Knowledge Base:
129444 XL7: 'Save As Type' Box Contains Only Excel Workbook
If you change only the filename, the Multi-User Editing feature is not
turned on in the new file. This behavior is by design, because normally,
when you save a shared file, you do so to make your own local copy.
Therefore, the Multi-User Editing feature is not "saved" to the new copy of
the file.
WORKAROUNDS
To work around this behavior, you can turn on the Multi-User Editing
feature in the new file by doing the following:
- On the File menu, click Shared Lists, and then click the Editing tab.
- Click the Allow Multi-User Editing check box.
Note that if the format of this file is not Microsoft Excel workbook, the
Save As dialog box appears, and you must save the file in the Microsoft
Excel workbook format in order to save the file with the Multi-User Editing
feature turned on.