Is it possible to encrypt an email message WITHOUT encrypting the attachment(s)?

Question

Is it possible to encrypt an email message WITHOUT encrypting the attachment(s)?

Teresa Stenson-George 1

Is it possible to encrypt an email message WITHOUT encrypting the attachment(s), i.e. Excel and/or Word files? We exchange encrypted emails between certain staff members that contain Word and/or Excel files. The attachments end up locked and cannot be opened on the recipient end

Faery Fu-MSFT 19,751 Reputation points Moderator

2022-06-08T02:36:57.267+00:00
Hi @Teresa Stenson-George ,
I am afraid it is not feasible to encrypt email without encrypting attachment.

Besides, according to my search on the error you provided, it because that the user doesn’t have permission to open this file.
To better understand your situation, I want to confirm the information below with you:

May I know if the attachment has been stored in OneDrive for Business or SharePoint Online or the local?

Does this issue occur to all recipients or to specific recipients?
Teresa Stenson-George 1 Reputation point

2022-06-08T14:05:52.52+00:00
May I know if the attachment has been stored in OneDrive for Business or SharePoint Online or the local? No.

Does this issue occur to all recipients or to specific recipients? All

The sender is working remotely and connects via VPN/Remote Desktop. Could that be a factor? Other staff work inside the office connected directly to the domain/server. She gets the same issue when sending encrypted emails with attachments (Excel or Word) to our company accountant's office.
Faery Fu-MSFT 19,751 Reputation points Moderator

2022-06-09T08:43:03.717+00:00

Hi @Teresa Stenson-George ,
Thanks for your reply.
In order to further confirm the issue, it is recommended the sender send an encrypted email with a local attachment and see if the issue continues.
Teresa Stenson-George 1 Reputation point

2022-06-09T17:22:09.643+00:00

I tried that, created an Excel and Word file, attached them to an email and sent it encrypted. It did the exact same thing, even when I sent it to myself (local and outside email addresses).
Faery Fu-MSFT 19,751 Reputation points Moderator

2022-06-13T08:05:47.86+00:00

Hi @Teresa Stenson-George ,

Based on my search, I found a similar thread: Some Excel Files - "You don't have permission to open this file" even though I am the administrator
In order to verfiy whether the problem is caused by something that runs on the PC, it is recommended you perform a clean boot, then check if the problem persists.
Here is an official document you can refer to: How to perform a clean boot in Windows
If you still need further help on this, feel free to contact us.