Hi @Mason McClurg ,
According to your description, you want to transfer a large number of local excel files to OneDrive/SharePoint for online storage, right?
To migrate your files and workbooks to OneDrive for Business, you can use the OneDrive sync app to sync files between your computer and Microsoft 365, which allows you to work with synced files directly in File Explorer and the apps you use. Whenever you are online, any changes that you or other users make will sync automatically. However, changing the location of your files on your computer or device requires stopping the synchronization and then setting up a new synchronization.
To ensure that your links between workbooks are not broken, you should make sure that all of the files are in the same folder on OneDrive for Business. You can also update the links in your workbooks to point to the new location on OneDrive for Business.
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