You can't sync files or folders in Office 365, or receive errors when you open files in Office Online
This article applies only to the previous OneDrive for Business sync client (groove.exe). In most cases, we recommend that you use the newer OneDrive sync client (onedrive.exe) instead. Which version of OneDrive am I using?
After you upload or create a folder that's named "_private" in Microsoft SharePoint Online or in OneDrive for Business, you experience one or more of the following issues:
When you synchronize the _private folder by using the OneDrive for Business sync app, you receive the following error message for any files that are in the folder:
- This file name contains invalid characters.
When you synchronize the _private folder by using the OneDrive for Business sync app, the folder itself is synchronized, but no files in the folder are synchronized.
You try to open an item that exists in the _private folder in Microsoft Office Online, you receive the following error message:
- Sorry, this document can’t be opened for editing.
To work around this issue, use a folder name other than "_private" in SharePoint Online or OneDrive for Business.
This issue occurs because a folder that's named "_private" isn't supported in SharePoint Online.
Still need help? Go to Microsoft Community.