Hi @Kerr Moncrieff
Are you using personal OneDrive or OneDrive for Business? Besides, is the email you receive shared files a ***Microsoft account ***or an account form organization?
Please sign into OneDrive online, then check whether you may access shared files under: Shared > With you.
If you still cannot access the shared files online, it's best to re-share this folder to your email.
Sign in account in the private mode of browser, clear the cookies and browsing data.
Plus, if you are using OneDrive for Business, you may refer to: https://learn.microsoft.com/en-us/sharepoint/troubleshoot/sharing-and-permissions/this-item-might-not-exist-error. Using the Microsoft Admin site to troubleshoot.
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