Unexpected behavior: Receive-Only folder propagates local additions to a Send-Only device

Support
1

Hello,

I’m encountering a behavior that seems to contradict the documented semantics of the folder types “Send Only” and “Receive Only”.

I will describe the situation as clearly as possible.

Environment

  • Device A (iMac-02): Folder type set to Send Only

  • Device B (iMac-01): Same folder set to Receive Only

  • Both devices run Syncthing v1.xx on macOS

  • The folder is shared only between these two devices

  • No overrides were triggered manually, and no errors were shown

Expected behavior

According to the documentation and previous discussions in the forum:

  • A Receive-Only folder should never announce or propagate local additions to the cluster.

  • Local additions should remain local and be shown as “Local Additions”.

  • A Send-Only folder should never accept remote changes.

Under these rules, it should be impossible for a manually created file within the Receive-Only folder on Device B to appear on Device A.

Actual behavior

  1. A new folder/file was created manually in the Receive-Only folder on Device B.

  2. Shortly afterwards, this file also appeared on Device A, even though Device A is configured as Send Only.

  3. Device B did not show any “Local Additions” warning.

  4. No override or confirmation was performed at any point.

  5. Despite this, the file was transferred to the Send-Only device.

This appears to contradict both the documented behavior and the intended one-way setup.

Steps to reproduce

  1. Configure a shared folder as Send Only on Device A.

  2. Configure the same folder as Receive Only on Device B.

  3. Let them connect normally.

  4. Create a new file or directory manually inside the folder on Device B.

  5. Observe whether Device A receives the new file.

Question

Is this behavior expected for some reason, or does this indicate a possible issue? If this is known or documented somewhere, I would appreciate clarification. If needed, I can provide logs, config files or further details.

Thank you.

Arben

2

Assuming you had no mixup between Device A and Device B, and they actually have the folder types listed above, definitely a bug.

Logs would be nice to tell whether it’s behaving the way it seems like.

1 Like
3

Yeah, that totally doesn’t happen for me.

4

Thank you for your quick reply and your offer to help. I believe I have identified the cause of the issue.

On iMac-02 I had my main Documents folder shared with iMac-01 using:

  • iMac-02 → Send & Receive

  • iMac-01 → Receive Only

However, inside this Documents folder I also had a separately shared subfolder. That subfolder was configured as:

  • iMac-02 → Send & Receive

  • iMac-01 → Send & Receive

This seems to have caused conflicting behaviour.

After removing this subfolder from the shared folders on both devices, the issue stopped immediately. At the moment everything is working as expected, and I hope it remains stable.

If anything changes, I will report back.

2 Likes
5

The file that was propagated the wrong way was in the subfolder? If so it makes sense.

6

No, I was able to delete something, a folder or a file, doesn’t matter, in the main ‘Documents’ folder on iMac 01, where it was set to ‘receive only’. This deletion was then also carried out in the iMac 02 main folder, where ‘send and receive’ was enabled.

7

This still seems like a bug if it’s as described.

1 Like
8

I’m pretty sure this is just a misconfiguration / misunderstanding of nested folders.

9

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