Dropbox Smart Sync Not Showing Up: A Mysterious Placeholder Phenomenon

Have you ever noticed that some files in your Dropbox account are not showing up, despite being synced? This phenomenon is more common than you think, and it's related to the way Dropbox handles online-only files. In this article, we'll dive into the world of reparse points and placeholders to uncover the truth behind this mystifying behavior.

Firstly, let's clarify what a placeholder is in this context. A placeholder is a file that appears as though it doesn't exist on your local machine, but actually does. It's a way for Dropbox to signal that a file is online-only, meaning it's not stored locally. However, when you use an online-only file, it can sometimes enter a 'halfway house' state where it no longer shows up as a reparse point, but still appears with parentheses indicating its size.

This behavior has been observed by many users, and the phenomenon is often linked to RoboCopy, a powerful command-line utility that allows you to copy files between locations. When using RoboCopy on an online-only file, it can lose its reparse point status, remaining a placeholder with parentheses, and even end up on the target location marked as a placeholder.

So, what's behind this strange behavior? The answer lies in the way Dropbox handles attributes. Specifically, when a file has the 'Offline' attribute (FILE_ATTRIBUTE_OFFLINE), it will display parentheses. This attribute is used to indicate that the file is not available locally, but can be accessed online.

In the case of SmartSync'd files, things get even more complicated. When a file is in an online-only state, it's visible as a reparse point with placeholders and size in parentheses, and the space isn't occupied. However, when you use the file, it comes back to disk, and the parentheses disappear, but the file remains a reparse point.

Moreover, if you clear the Windows space for a particular file, it becomes a placeholder with the size shown in parentheses on the relevant dir output while remaining a reparse point.

In contrast, OneDrive handles files differently. Each file in the relevant Windows folder is a reparse point (visible through dir /al), making it easier to identify and manage online-only files.

Despite numerous discussions about Dropbox's SmartSync feature, this specific phenomenon seems to be underreported. However, by understanding how placeholders and reparse points work, you can better navigate the complexities of syncing your files across devices.

In conclusion, the mysterious placeholder behavior observed in Dropbox's SmartSync feature is a result of the way attributes are handled. By knowing what to look for and how to manage online-only files, you can avoid frustration and ensure seamless file synchronization across devices.

Dropbox smart sync not showing up