office 365 - outlook now opening excel attachments as read only

Captain Kirk 121 Reputation points
2023-01-04T16:00:47.517+00:00

we have office 365, and suddenly today, I am seeing lots of people complaining that when they receive an excel spreadsheet via email, it is always opening in Read Only mode.
I have tried in Excel going to Trust Center and unchecking everything under protected view, but that did not help.
its gotta be a 365 setting then, right? a couple of weeks ago we purchased Defender for 365, but If that was the culprit I would have thought we had seen this problem before now.
what else could be happening, what else can I look at?

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  1. Emily Hua-MSFT 27,546 Reputation points
    2023-01-05T09:09:17.643+00:00

    Hi @Captain Kirk

    From an excel perspective, I want to confirm that do these Excel files contain macros?
    If you can download these Excel files, please download it to local machine, and right-click them > Propertities > Make sure these files are not blocked.
    276433-capture1.png
    Then go to File > Info, check whether you can select Remove protection.

    Besides, does this issue occur with other Office files, such as Word documents?
    Please double click the the email > Message > Actions > Edit Message, check whether the attachments still be opened as read-only.
    276451-capture2.png

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