The forecast that will not recalculate
Your finance colleague emails you a file named Q1-forecast.xlsx. You open it and the formula bar is greyed out; a yellow bar reads PROTECTED VIEW and the sheet will not accept typing. After you click Enable Editing, the summary total in C18 still shows 1,302.50 even though you change the input in C5 from 400 to 500. The status bar at the bottom reads 'Calculate' rather than 'Ready'. A separate message from the colleague says she has just corrected a figure and asks why your copy does not show it. You also notice the workbook has never been saved to a shared location - it arrived as an attachment, and two other people in the team are working from the same email.
1. The yellow bar offers 'Enable Editing'. What does that choice actually change, what risk does it carry, and what should you do when the sender is unknown?
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What the bar means. Protected View opens the file in a restricted sandbox: content is visible but nothing is recalculated or editable, so the grey formula bar is expected behaviour, not a sign of corruption.
- Enable Editing lifts the sandbox for this session only. The risk is real: an .xlsx cannot store macros, but it can carry external links, DDE payloads and exploits aimed at the reader, and the sender's account may itself be compromised.
- Enable it only if you know the sender and were expecting the file.
- Do not solve the annoyance by switching Protected View off globally in Trust Center. That removes the check for every file you ever open, including the one that matters.
- If the sender is unknown, leave Protected View on, enable nothing, and verify through a second channel before opening.
The judgement being tested is that convenience and trust are separate decisions.
2. C18 does not update when C5 changes. Explain the cause, give a fix that changes no settings, and give the permanent fix. Which would you apply to a workbook you are about to send on, and why?
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Cause. Calculation Options is set to Manual, which is why the status bar shows 'Calculate' (pending work) instead of 'Ready'. The stored values are simply stale.
- One-off fix, no settings changed: press F9 to recalculate all open workbooks, or Shift+F9 for the active sheet only. Ctrl+Alt+F9 forces a complete rebuild, useful when dependency chains look wrong.
- Permanent fix: Formulas > Calculation Options > Automatic. Note the third option, 'Automatic Except for Data Tables', which is a common hidden cause of 'it recalculates everything but this one grid'.
- Before sending: set Automatic. The setting is saved inside the workbook, so a recipient who opens a Manual file sees frozen totals and concludes your numbers are wrong. Also check File > Options > Formulas for a circular-reference warning before release.
Recalculating is a two-second fix for you and an invisible trap for everyone downstream.
3. The colleague's correction is not in your copy. Explain why, and outline the two realistic ways of working so this stops happening.
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Why. An email attachment is a snapshot, not a link. Excel has no mechanism to merge her edit into your copy; the two files diverge the moment either is saved, and nothing warns you until someone compares totals.
Option 1 - co-author on OneDrive or SharePoint. Store one file in the cloud, open it from there, keep AutoSave on. Edits merge live and presence indicators show who is where. Constraints: modern file format, no legacy 'shared workbook' mode, and some features (certain merged-cell layouts, older add-ins) block co-authoring.
Option 2 - disciplined versioning. One nominated master, filenames carrying initials and date, and someone responsible for reconciling changed cells rather than replacing whole files. Track Changes or a compare tool helps, but both are weaker than co-authoring and easy to skip under deadline.
The dangerous habit to name explicitly: saving your older copy over her newer one. Excel warns, users click through, and the correction disappears silently.