Excel popup on opening "This document is both encrypted and password protected"

Question

Hi there,

I have a user who has the following popup every time they open Excel, even if they are not opening a document directly:

The version of Office is Microsoft 365 MSO 16.0.14131.20296 64-bit.

I have found a number of older posts related to this issue (such as this one) that all recommend creating a reg key under HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Common\Security, however as I am on the latest Office, I only have 16.0. I have tried to create the "Security" key and then the DWORD value in my corresponding 16.0 folder but it makes no difference.

I have also tried both a quick and online repair of Office.

Any other suggestions would be greatly welcome.

Answer 1

Hi all,

I have solved it - a fairly obvious solution I did not consider for some reason. I created the NoPromptForRC4Encryption key (and set value to 1) under HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Common\Security and I am no longer receiving the prompt.

Thanks for all your help.

Thanks,
Jamie

Answer 2

Hi @JamieHassallClarke-8015,
Based on your description, this problem only appear in a specific user.
Did this problem appear in all Excel Workbooks or specific Workbook? Where did you store the file?
Try this method:

*HKCU\Software\Microsoft\Office\16.0\<application>\Security\Crypto*

Create a registry key: CompatMode and set to 0.

Try it and check the result, please let us know if you would like further assistance.

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Answer 3

Just do a Save As and save as the new format.

Answer 4

Hi @JamieHassallClarke-8015

Fixing this kind of issues isn't in my area of expertise + I really don't like
When my PC becomes unstable (very very rare) for a reason or another most of the time I clean-up the room and re-install as my experience tells me that trying to fix something I don't really understand or that should not happen: 1) Can take a lot of time; 2) Risk is quite high that the fix will only be a short-term one and I'll face some other issues later

If it was me, given there's only have 1 user experiencing the issue I would be very pragmatic:

• See if issue persists starting Excel in Safe Mode
  If no issue, it's highly probable there's an add-in or something similar that's the root cause
  Check the content of XLSTART folder, just in case
• If issue persists in Safe mode, create a new user account on that PC
• If issue persists with a new account => Office uninstall support tool > Re-install

Hope this makes sense