Network disconnection causing data loss in saved MS Excel files due to potential overwriting when reverting back to the file version preceding the disconnection.

Hi,

Our company makes use of lists in Excel workbooks that are updated by multiple personnel.

Excel version: Microsoft 365 MSO (Version 2409, Build 16.0) 32-bit

We have several reporting of loss of "saved" data in these workbooks.

The following is a descriptive step-by-step sequence of events:

• Personnel A opened the excel Workbook with modify rights (not read-only) and updated the worksheet. Personnel C printed a hardcopy.
• Personnel B opened the excel Workbook with modify rights (not read-only) and updated the worksheet. Personnel C printed a hardcopy.
• Personnel B's data is lost.

Since we have proof form Personnel C's hardcopies that both personnel A & B versions were saved, my assumption is that:

• Personnel A opens the excel book with modify rights, starts updating the worksheet and gets disconnected from the network.
• <Assumption> Microsoft Office Excel keeps a snapshot of Personnel A, version (A).
• Personnel B opens the same workbook with modify rights and updates the excel worksheet, closes the file, version (B).
• <Assumption> The issue potentially crops up when Personnel A reconnects to the network and the Microsoft Office rewrites the file with Version (A) and consequently the updates of  Version (B) will be lost.

I have two queries:

1. Are my aforementioned assumptions possible/correct?
2. What can be done to prevent the reoccurrence of this issue?

thank you in advance for your help,

K