Hi Mandy Lewis,
Since the issue appears to be related to Personalization settings, I also recommend testing with a new Windows user account:
- Open Settings > Accounts > Other users.
- Select Add account.
- Choose I don't have this person's sign-in information > Add a user without a Microsoft account.
- Create a temporary local account and sign in to it.
- Check whether you're able to change the desktop background from Settings > Personalization > Background.
If the new account works normally, that would suggest the issue may be limited to your current Windows profile rather than Windows itself.
Additionally, could you share your Windows version and build number? You can check this by pressing Win + R, typing winver and sharing a screenshot or the version/build information shown in the About Windows window.
I hope these suggestions help. When you have a chance, please share the winver information and let me know whether the same behavior occurs in the newly created account.
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