+1

A sync client for Windows would be my personal priority, but Android is a start. Basically a replacement for Google Drive, which I'm still using as the sync feature is missing from Proton

This feature is absolutely critical for Proton Drive to be able to replace any other cloud storage provider.

Even more critical than a desktop sync client for Linux.

allow proton drive to integrate with android systems on phones so it shows up as an option to pull files from for other apps such as photo editing apps, as it currently does no do so, only the phone native option shows up

First truly e2e encrypted service that offers this gets my money for the next decade at least.

Without this capability, it is impossible to use Proton Drive to synchronize my music, my Obsidian vault, any documents, or really anything I need to be able to access with other apps (which is, y'know, basically everything!).

I want to be able to use Proton Drive as my generalised cloud service, but right now it is effectively just a photo backup tool, at least where my phone is concerned.

Highly crucial! Was about to subscribe to the proton ecosystem until I ran into this issue. Holding off on that until I can sync my obsidian vault across my windows and android devices.

Yes. I have several apps that run scheduled local backups and I'd like to back the up automatically with Drive

This is also needed on Apple iOS.

I'm syncing Obsidian between two PCs with the desktop app, but without this feature I'm stumped when trying to also sync it to my Android device.

I am dumbfounded by the lack of functionality to not simply nominate folders for backup and background sync for Android I just bought a full licence and future renewals may depend on this. Proton products are otherwise brilliant but they need to keep up with competition.
Does anyone at Proton actually use this product? Seems not or they would have done this already. Photos are probably the least important thing I backup.

as long as the integration is not on the expense of security

For everyone still looking for this: There's an Android solution with RoundSync. The RoundSync app is an Android version of the Rsync client, and Rsync has beta support for ProtonDrive.
I use SeedVault to backup my device to a local folder, then RoundSync to 1-way sync those files to a folder in ProtonDrive. It works relatively well but obviously isn't as efficient or reliable as a native ProtonDrive solution would be.

I have literally this exact same situation!

I also need this feature, otherwise having Music in ProtonDrive is next to useless, as the app can't play the music and no other app can access the files.
Thank you

I too cannot use this as an alternative until I can have critical files synced across multiple devices. I understand there may be reticence to open this up to apps which already sync files, but if not please put it as the highest priority for new development. Otherwise the data we pay for is just a backup and files used and modified on multiple devices cannot be stored on Proton Drive.

This is crucial feature, even if it could be enabled for specific files (or better) folders. I need it to be able to save .kbdx files and for Obsidian. I use KeePassXC on my desktop and need it to sync with my phone (where I use KeePassDX).

Frankly, I like the suite of Proton applications, but this one problem is stopping me from investing in it as it will force me to use a competitor. This seems to be a bit of a trend in this forum.

Please developors.

First of all, i fully understand that shared storage is shared, and that therefore no guarantees of privacy or encryption can be made by Proton. If this function gets hidden behind a disclaimer, that's totally understandable.

However.
It is absolutely critical for me to be able to sync a folder (not just individual files) in shared storage. I cannot open each file through the proton drive app individually, that is insanity for collections of files that belong together, like pdfs, music. I also need it to automatically back up shared data generated by other apps. Without this feature, proton drive is nearly useless to me. Especially with a linux desktop client still not being available either.

I would need it to sync my task tool markdown files (opensource: logseq) and my music and audio books. Als for password safe files. Otherwise I can not access them from my other applications. This is really a crucial feature and would improve the experience and use of Proton Drive ten fold...

It's really needed ! Would love a message from project lead of where the project is in the roadmap !

Back when I used Google Device, I used an app called "DriveSync" that added this feature kinda. I still use google drive for some folders that I don't mind being exposed but having it all in proton itself would be sick and save me so much time when it comes to my automatons.