I have no clue why people still use it and I'd cut my losses if I were you, either backup to the cloud or pull from it, not both at the same time like an absolute tictac.
This is an instance of someone familiar with complex file access patterns not understanding the normal use case for these services.
The people using these bidirectional sync services want last writer wins behavior. The mild and moderately technical people I work with all get it and work with it. They know how to use the UI to look for old versions if someone accidentally overwrites their file.
Your characterization as complete chaos with constant problems does not mesh with the reality of the countless low-tech teams I've seen use Dropbox type services since they were launched.
No, I'm not joking. We used to allow arbitrary paths in a cloud API I owned. Within about a month someone had figured out that the cost to store a single byte file was effectively zero, and they could encode arbitrary files into the paths of those things. It wasn't too long before there was a library to do it on Github. We had to put limits on it because otherwise people would store their data in the path, not the file.
Reason - to not overcomplicate or give appearance of nickel-and-diming
Would there be any engineering/management pushback on the customer side? "we have to write a tiny script", "this is non-standard" / "why are you the only ones who charge us for filenames?"
(have limited knowledge here)
The sync application itself can handle this using openat(2) or similar and should probably be using that regardless to avoid races.
Point taken, although I still think it's better for cloud storage services to err on the side of compatibility, i.e. what's the lowest common denominator between Linux, macOS, Android, iOS from 10 years ago and Windows 7?
Avoid arbitrary limits on the length or number of any data structure, including filenames, lines, files, and symbols, by allocating all data structures dynamically.
What can get things into a weird state is if both machines are editing the same file while only one of them is actively syncing. But for basic backup and sync, this is extremely rare.
You can build such a system yourself quite trivially by getting an FTP account, mounting it locally with curlftpfs, and then using SVN or CVS on the mounted filesystem. From Windows or Mac, this FTP account could be accessed through built-in software.
If we remove the whole linux section and just ask "why not map a folder in Explorer" it's a reasonable question, probably even more reasonable in 2026 than in 2007. The network got faster and more reliable, and the dropbox access got slower.
It works perfectly fine as long as you keep how it works in mind, and probably most importantly don't have multiple users working directly on the same file at once.
I've been using these systems for over a decade at this point and never had a problem. And if I ever do have one, my real backup solution has me covered.
“Every file is only ever written to from a single client, and will be asynchronously made available to all other clients, and after some period of time has elapsed you can safely switch to always writing to the file from a different client”.
:P
That being said i understand how it works at a high level.
What do you use and how do you test / reconcile to make sure it’s not missing files? I find OneDrive extremely hard to deal with because the backup systems don’t seem to be 100% reliable.
I think there are a lot of solutions these days that error on the side of claiming success.
But the moment that hits normal users, yeah, mess
It is true that we recently updated how Backblaze Computer Backup handles cloud-synced folders. This decision was driven by a consistent set of technical issues we were seeing at scale, most of them driven by updates created by third-party sync tools, including unreliable backups and incomplete restores when backing up files managed by third-party sync providers.
To give a bit more context on the “why”: these cloud storage providers now rely heavily on OS-level frameworks to manage sync state. On Windows, for example, files are often represented as reparse points via the Cloud Files API. While they can appear local, they are still system-managed placeholders, which makes it difficult to reliably back them up as standard on-disk files.
Moreover, we built our product in a way to not backup reparse points for two reasons:
1. We wanted the backup client to be light on the system and only back up needed user-generated files. 2. We wanted the service to be unlimited, so following reparse points would lead to us backing up tons of data in the cloud
We’ve made targeted investments where we can, for example, adding support for iCloud Drive by working within Apple’s model and supporting Google Drive, but extending that same level of support to third-party providers like Dropbox or OneDrive is more complex and not included in the current version.
We are currently exploring building an add-on that either follows reparse points or backs up the tagged data in another way.
We also hear you clearly on the communication gap. Both the sync providers and Backblaze should have been more proactive in notifying customers about a change with this level of impact. Please don't hesitate to reach out to me or our support team directly if you have any questions. https://help.backblaze.com/hc/en-us/requests/new
We are here to help.