Thank you for posting your question in the Microsoft Q&A forum.
I'm sincerely sorry for any inconvenience and troubles this situation may have caused you.
According to your concern, I suggest you should double check these things:
1- Check if extend selection is enabled
Excel has Extend Selection mode which triggered by pressing F8 may have impact on how Shift + Arrow behaves. If the mode is on, you can turn this mode off by pressing Esc and see if the issue persists
2- Open Excel safe mode
Excel safe mode disables all add-ins and custom settings and makes it runs in the original state. You can try opening Excel safe mode by press Windows + R to open Run dialog box > type excel /safe > press OK to run and check if the issue persists there.
For further assistance, can you share more details about the situation:
- What is your current Excel version/build?
- Does the issue happen in all workbooks or just in specific ones?
Please understand that our initial response does not always resolve the issue immediately. However, with your help and more detailed information, we can work together to find a solution.
Thank you for your understanding and cooperation. If you have any questions or need further assistance, please feel free to share them in the comments so I can continue to support you.
I'm looking forward to your reply.
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