How can I enable the creation and editing of hyperlinks in shared Excel worksheets?

I had the same problem and fixed by using the =HYPERLINK function in the cell rather than the "insert hyperlink" option.

HYPERLINK(link_location, [friendly_name])

Make sure to place the location and friendly_name in quotes (" ").

Sharing a workbook disables several features in Excel.Hyperlinks, merged cells, charts, pictures and more. If the workbook is shared, you will not be able to use these features. If you un-share the workbook, these items should be availble again. This has been the case for a long time. This Excel 2003 article shows this, and this Excel 2010 article also shows this.

I can get around this by copying the hyperlink from a nonshared Excel file and pasting it into the shared Excel file.

This is not ideal and more work but could be helpful if you dont want to continually share and unshare.