I am working with a large Excel file (over 2000 lines and 20 columns)
that is shared by at least five users in different offices who are
likely running different versions of Excel. We are frustrated by the
fact that it often seems like saved data is missing. For example,
when the file is opened, it often appears as though cells in one of
the columns were not saved while data entered into another column at
the same time saved successfully.

What could be causing this? Is there a remedy?

Thank you.