[Zubersoft]

In order to get around issues with OneDrive for Business accounts, I had to switch to using a new approach that embeds the Drive ID in the file paths that are stored in the sync folder database. Your error is due to some kind of issue with this new approach where MobileSheets is requesting the file incorrectly (it is using the file path with the embedded Drive ID versus stripping it out like it's supposed to). Without having access to your library and your sync folder, I can't say why this occurred. If you clear out the sync folder, sync to the folder again and then sync your other device, I believe it should work. Something just probably got uploaded incorrectly at some point. I am not encountering any issues while synchronizing to OneDrive at the moment.

Mike