There is no default setting in Excel that works.
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One fix that does work is to create a macro that runs every time you open a file
https://social.technet.microsoft.com/Forums/office/en-US/a1f4d7b0-2f68-4f05-a673-717467141c5e/excel-2010-set-default-zoom-setting
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https://excel.tips.net/T002668_Always_Open_at_100_Zoom.html
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Submit a feedback to MS asking for a user controlled option to set default zoom level.
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Feedback Hub
For a couple of years now MS has had a "feedback" process that allows users submit bug reports / problems, suggestions and new feature requests directly to MS developers and managers. You can submit feedbacks from within many MS apps, or you can use the Win10 “Feedback Hub” app.
https://answers.microsoft.com/en-us/msoffice/forum/all/microsoft-feedback-process/6f850368-8c86-481d-a207-d95b265c4be4
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But don't "expect" anything from MS.
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We identify bugs, they pick which they will work on and when they will release them, for testing by Insiders and to general public.
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They will make fixes and changes on their own schedule.
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They will not provide much, if any, advance notice of what they are working on and when it will be released.
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Hint : get a “share” link to your feedback (may take a couple of minutes to process the initial submission of the feedback) and post the link back to this question. That way if someone finds this question they will be able to link directly to your feedback so they can vote for it and add their comments. The more feedback on a subject, the more likely it is to be acted on.
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