Dear Jonathan,
Good day! Thanks for posting in the community. We are happy to help you.
According to your description, I would like to collect some information to better understand the situation.
- Since you mentioned the situation won't happen when you insert a local file as an Object, I would like to know more details about how you insert the SharePoint/OneDrive file. May I know if you have installed the OneDrive client and inserted the online files by selecting them from the OneDrive local sync folder in the File Explorer? If so, what if you paste the URL directly in the File Explorer as shown in the screenshot below, do these error messages pop on again?
For the URL, here's an example, you need to edit the bold part. https://tenantname.sharepoint.com/sites/sitename/libraryname
- Please provide your Office version
Click File> Account, please take a screenshot including Subscription Product and About Excel.
Also, you can try the following suggestions to troubleshoot further.
- Please run Excel, click File> Options> Advanced> under General area, please tick/untick "Ignore other applications that use Dynamic Data Exchange (DDE)" depending on what it is to start with. After that, please restart Excel and check again.
- Please try to set Excel into Safe Mode, then insert the online file again. Check if the situation still happens or not.
Close Excel, press win + R, in the Run box, type excel /safe, and click OK
We look forward to your response. Thanks for your cooperation.
Sincerely,
George | Microsoft Community Moderator