Today I was trying to use SyncBackPro to backup some files to OneDrive for Business (also styled as Office 365). I was trying to do some tests, but the backup kept failing, and the SyncBackPro log stated "Directory does not exist on Office 365 and cannot be created: The filename (Old_files) may not be allowed on this cloud service. NameAlreadyExists: A resource with the same name already exists".
After trying a few things, I discovered that all I needed to do was to change the name of the local folder from Old_files to something else.
To test this a bit further, I tried manually creating a folder called Old_files in the web interface, and the folder was created. However, the actual folder name that was created was not "Old_files" but had been changed silently to "Old_files_". So my guess is that Old_files is a folder that gets created automatically in all OneDrive files, and that it is hidden completely from the user. Likely it contains backup files that will be automatically deleted at some point. It was interesting.
