jacoch

Well, I would not say that it doesn't allow to set file modification time. It works properly on the shares. But maybe BTSync client doesn't support my configuration yet. I'm using DSM 6 beta and btrfs as FS.

Modifications times are fine. That's why I thought about the creation time. It's the only difference. So I looked at the logs more closely and noticed an error when setting attributes. That could be the cause of the troubles. Here are some interesting entries from my logs (it's a file uploaded on January 13th reverting to a version from January 6th). Maybe you can explain more clearly why the old file finishes to be sent to other peers. [20160113 14:56:25.726] MC[C17F] [7E7A]: will request nodes for /My/Path/To/File.pdf [20160113 14:56:27.187] MC[C17F] [7AF7]: will request nodes for /My/Path/To/File.pdf [20160113 14:56:27.308] MC[C17F] [7AF7]: processing nodes message for /My/Path/To/File.pdf [20160113 14:56:27.308] MC[C17F] [7AF7]: will request files for /My/Path/To/File.pdf [20160113 14:56:27.429] MC[C17F] [7AF7]: Local file My/Path/To/File.pdf is older than remote t:1452691269/1452693379 ot:28110/2210841 o:10CA626E2DA8A6F6AF702A6EE757641ABC7FEE40/10C0FE7D53478F7664D731BDBAEE10705B527E7A Wed, 13 Jan 2016 13:21:09 GMT / Wed, 13 Jan 2016 13:56:19 GMT [20160113 14:56:27.429] JOURNAL[C17F]: got file from remote: "My/Path/To/File.pdf" state: 1 type: file total:17 have:17 size:540230 t:1452693379 mt:1452693379 ot:2210841 o:10C0FE7D53478F7664D731BDBAEE10705B527E7A h:813725282900FCC03403E890737182DAB70E0A2D Wed, 13 Jan 2016 13:56:19 GMT [20160113 14:56:27.453] Update have pieces for file "/volume1/Plurial/Internet 08/My/Path/To/File.pdf", was: 17, now: 17 [20160113 14:56:27.453] SyncFileEntry: writing file attributes to file "/volume1/Plurial/Internet 08/My/Path/To/File.pdf", mt:1452693379 Wed, 13 Jan 2016 13:56:19 GMT [20160113 14:56:27.453] SyncFileEntry: Failed to write attributes for file /volume1/Plurial/Internet 08/My/Path/To/File.pdf - 1 [20160113 14:57:33.850] Update have pieces for file "/volume1/Plurial/Internet 08/My/Path/To/File.pdf", was: 17, now: 0 [20160113 14:57:33.875] Update have pieces for file "/volume1/Plurial/Internet 08/My/Path/To/File.pdf", was: 0, now: 17 [20160113 14:57:33.875] JOURNAL[C17F]: entry "/volume1/Plurial/Internet 08/My/Path/To/File.pdf" state: size:540230 mt:4294967295 t:1452693453 h:813725282900FCC03403E890737182DAB70E0A2D (new torrent for file) Wed, 13 Jan 2016 13:57:33 GMT [20160113 14:57:33.876] JOURNAL[C17F]: setting time for file "/volume1/Plurial/Internet 08/My/Path/To/File.pdf" to 1452693453 Wed, 13 Jan 2016 13:57:33 GMT [20160113 14:57:33.876] SyncFileEntry: Set owner time for entry "/volume1/Plurial/Internet 08/My/Path/To/File.pdf" to 28266 [20160113 14:57:33.877] JOURNAL[C17F]: entry "/volume1/Plurial/Internet 08/My/Path/To/File.pdf" state: size:540230 mt:1452084885 t:1452693453 h:813725282900FCC03403E890737182DAB70E0A2D (file updated) Wed, 06 Jan 2016 12:54:45 GMT / Wed, 13 Jan 2016 13:57:33 GMT [20160113 14:57:41.888] MC[C17F] [7AF7]: will request nodes for /My/Path/To/File.pdf [20160113 14:57:42.008] MC[C17F] [7AF7]: processing nodes message for /My/Path/To/File.pdf [20160113 14:57:42.008] MC[C17F] [7AF7]: will request files for /My/Path/To/File.pdf [20160113 14:57:42.097] MC[C17F] [7E7A]: will request nodes for /My/Path/To/File.pdf [20160113 14:57:42.130] MC[C17F] [7AF7]: Local file My/Path/To/File.pdf is newer than remote t:1452693453/1452693379 ot:28266/2210841 o:10CA626E2DA8A6F6AF702A6EE757641ABC7FEE40/10C0FE7D53478F7664D731BDBAEE10705B527E7A Wed, 13 Jan 2016 13:57:33 GMT / Wed, 13 Jan 2016 13:56:19 GMT [20160113 14:57:42.130] MC[C17F] [7AF7]: will send file /My/Path/To/File.pdf

I'm facing the same problem. I had for several weeks only two computers synced together (Win10 and OSX). No trouble. Then I added a Synology NAS to the peers (running latest 2.2.5-1 version). That was the beginning of the troubles. By looking at the logs and file creation times, it seems that the creation time is wrong on Synology. It's set to the date the file was copied to. So when my computer changes a file, keeping its original creation time, the NAS thinks its version is newer and overwrite the changes. Why is file creation time used to check which file is newer? Most of the time, creation date is not changed by OSes. Is this problem limited to Synology?