johannes
May 31, 2026, 5:57pm
1
All four mentioned devices are on 2.1.0, a mixture of Windows and Linux machines.
On Device A (receive-only), I had to start over with a new Syncthing database due to a mishap while trying to move the database to a different folder, but synced files were kept intact. The database is now recreated, and Device A thinks the sync folder is up-to-date: Certainly, the files on-disk are all there as before, they are identical to the files on the other machines, and the file count in the shared folder is identical on all devices. So from Device A’s perspective, everything is alright. However, two other Device B & C (both configured as send & receive) show that about 21,000 files are out of sync on Device A. I did skim the list of files that are reported to be out of date and they are all present in the sync folder on Device A. Device B & C both make no progress on this number.
As far as a fourth Device D is concerned, Device A is up-to-date and has no out-of-sync files.
How can I diagnose what’s going wrong here?
calmh
May 31, 2026, 6:53pm
2
Firstly, since the device is receive-only and you did a strange thing, see if it has a “revert local changes” button. If so, press it.
If not:
Pick a representative out-of-sync file. Run syncthing debug database-counts <folderID> and syncthing debug database-file <folderID> <filename> on both sides and paste the output. The filename part in the latter command accepts a partial match, so you can give just the file name without the path in the folder etc.
E.g., what we expect to see:
jb@jbo-m3wl72rv:~ % syncthing debug database-counts w3ejt-fn4dm
DEVICE TYPE FLAGS DELETED COUNT SIZE
-local- FILE ------- --- 0 0
-local- FILE ------- del 0 0
...more...
PSEUDOP DIRECTORY -nG---- --- 0 0
PSEUDOP DIRECTORY -nG---- del 0 0
jb@jbo-m3wl72rv:~ % syncthing debug database-file w3ejt-fn4dm 20150103-145351-0345.jpg
DEVICE TYPE NAME SEQUENCE DELETED MODIFIED SIZE FLAGS VERSION BLOCKLIST
-local- FILE 2015/Hemma/iPhone/20150103-145351-0345.jpg 202795 --- 2015-04-26T19:54:27Z 1073016 --G---- PSEUDOP:1744214844 tOJxBYSV
PSEUDOP FILE 2015/Hemma/iPhone/20150103-145351-0345.jpg 673968 --- 2015-04-26T19:54:27Z 1073016 ------- PSEUDOP:1744214844 tOJxBYSV
Ideally, also take a support bundle (Actions -> Support bundle in the GUI) from both sides. That contains your config and some logs and metrics, in lightly redacted form, so you can send them as direct messages if you prefer.
johannes
June 2, 2026, 7:43pm
3
It is in completely pristine state, no local changes.
But I have a hunch that the real problem is that I moved the database from the OS microSD card to an external hard drive to reduce flash memory wear. Syncthing is completely unresponsive for large amounts of times, while it was mostly fine before the move. So it could be that the other clients are stuck in eternal limbo that they are not able to verify that all files are synchronized (but they still do manage to realize that files I have synced since then have been updated on the remote client as well).
I’m not even able to create the support bundle on that machine because the browser tries loading the page but then it’s just stuck forever.
Anyway, one of the send-receive clients:
syncthing debug database-counts v3frg-au6mt
DEVICE TYPE FLAGS DELETED COUNT SIZE
-local- FILE ------- --- 0 0
-local- FILE ------- del 0 0
-local- FILE ----r-- --- 0 0
-local- FILE --G---- --- 526454 848162321736
-local- FILE --G---- del 6459 0
-local- FILE --G-r-- --- 0 0
-local- DIRECTORY ------- --- 0 0
-local- DIRECTORY ------- del 0 0
-local- DIRECTORY --G---- --- 27451 3513728
-local- DIRECTORY --G---- del 611 78208
BVTQQPI FILE ------- --- 460118 841187782873
BVTQQPI FILE ------- del 5301 0
BVTQQPI FILE --G---- --- 0 0
BVTQQPI FILE --G---- del 11 0
BVTQQPI FILE -nG---- --- 0 0
BVTQQPI FILE -nG---- del 0 0
BVTQQPI FILE v------ --- 66336 0
BVTQQPI FILE v------ del 11 0
BVTQQPI DIRECTORY ------- --- 24632 3152896
BVTQQPI DIRECTORY ------- del 548 70144
BVTQQPI DIRECTORY -nG---- del 0 0
BVTQQPI DIRECTORY v------ --- 2819 360832
BVTQQPI DIRECTORY v------ del 4 512
THJTAAV FILE ------- --- 526394 848100106215
THJTAAV FILE ------- del 6027 0
THJTAAV FILE --G---- --- 0 0
THJTAAV FILE --G---- del 120 0
THJTAAV FILE -nG---- --- 0 0
THJTAAV FILE -nG---- del 0 0
THJTAAV FILE v------ --- 60 0
THJTAAV FILE v------ del 0 0
THJTAAV FILE v-G---- del 0 0
THJTAAV DIRECTORY ------- --- 27442 3512576
THJTAAV DIRECTORY ------- del 598 76544
THJTAAV DIRECTORY --G---- del 0 0
THJTAAV DIRECTORY -nG---- --- 0 0
THJTAAV DIRECTORY -nG---- del 0 0
THJTAAV DIRECTORY v------ --- 9 1152
HVUDRTK FILE ------- --- 0 0
HVUDRTK FILE ------- del 0 0
HVUDRTK FILE --G---- --- 0 0
HVUDRTK FILE --G---- del 0 0
HVUDRTK FILE -nG---- --- 0 0
HVUDRTK FILE -nG---- del 0 0
HVUDRTK FILE v------ --- 0 0
HVUDRTK FILE v-G---- --- 0 0
HVUDRTK DIRECTORY ------- --- 0 0
HVUDRTK DIRECTORY ------- del 0 0
HVUDRTK DIRECTORY -nG---- --- 0 0
HVUDRTK DIRECTORY -nG---- del 0 0
VHQXY2U FILE ------- --- 506758 773377308109
VHQXY2U FILE ------- del 4005 0
VHQXY2U FILE --G---- --- 0 0
VHQXY2U FILE --G---- del 10 0
VHQXY2U FILE -nG---- --- 0 0
VHQXY2U FILE -nG---- del 0 0
VHQXY2U FILE v------ --- 0 0
VHQXY2U FILE v-G---- --- 0 0
VHQXY2U DIRECTORY ------- --- 25834 3306752
VHQXY2U DIRECTORY ------- del 450 57600
VHQXY2U DIRECTORY --G---- del 0 0
QLFSI6G FILE ------- --- 526454 848162321736
QLFSI6G FILE ------- del 7 0
QLFSI6G FILE -nG---- --- 0 0
QLFSI6G FILE -nG---- del 0 0
QLFSI6G DIRECTORY ------- --- 27451 3513728
QLFSI6G DIRECTORY ------- del 1 128
QLFSI6G DIRECTORY -nG---- --- 0 0
QLFSI6G DIRECTORY -nG---- del 0 0
syncthing debug database-file v3frg-au6mt trinity-samples.zip
DEVICE TYPE NAME SEQUENCE DELETED MODIFIED SIZE FLAGS VERSION BLOCKLIST
-local- FILE Audiosoftware/Alchemist (Trinity To Triton)/trinity-samples.zip 3259103 --- 2022-03-16T18:52:42.7549393Z 41680330 --G---- BMXPQP6:1758805844 Fi2Sb1ZW
BVTQQPI FILE Audiosoftware/Alchemist (Trinity To Triton)/trinity-samples.zip 3293478 --- 2022-03-16T18:52:42.7549393Z 41680330 ------- BMXPQP6:1758805844 Fi2Sb1ZW
THJTAAV FILE Audiosoftware/Alchemist (Trinity To Triton)/trinity-samples.zip 3280118 --- 2022-03-16T18:52:42.7549393Z 41680330 ------- BMXPQP6:1758805844 Fi2Sb1ZW
QLFSI6G FILE Audiosoftware/Alchemist (Trinity To Triton)/trinity-samples.zip 3408259 --- 2022-03-16T18:52:42.7549393Z 41680330 ------- BMXPQP6:1758805844 Fi2Sb1ZW
-local- FILE Audiosoftware/Alchemist/trinity-samples.zip 3259104 del 2025-09-25T13:12:39.7549393Z 0 --G---- BMXPQP6:1758805959 -nil-
BVTQQPI FILE Audiosoftware/Alchemist/trinity-samples.zip 3293479 del 2025-09-25T13:12:39.7549393Z 0 ------- BMXPQP6:1758805959 -nil-
THJTAAV FILE Audiosoftware/Alchemist/trinity-samples.zip 3280119 del 2025-09-25T13:12:39.7549393Z 0 ------- BMXPQP6:1758805959 -nil-
And the receive-only client (in case there are any inconsistencies):
syncthing debug database-counts v3frg-au6mt
DEVICE TYPE FLAGS DELETED COUNT SIZE
-local- FILE ------- --- 0 0
-local- FILE ------- del 0 0
-local- FILE ---e--- --- 0 0
-local- FILE --G---- --- 526441 847580937619
-local- FILE --G---- del 6555 0
-local- FILE --Ge--- --- 0 0
-local- DIRECTORY ------- --- 0 0
-local- DIRECTORY ------- del 0 0
-local- DIRECTORY --G---- --- 27449 3513472
-local- DIRECTORY --G---- del 612 78336
BMXPQP6 FILE ------- --- 526441 847580937619
BMXPQP6 FILE ------- del 6461 0
BMXPQP6 FILE --G---- del 11 0
BMXPQP6 FILE -nG---- --- 0 0
BMXPQP6 FILE -nG---- del 0 0
BMXPQP6 FILE v------ --- 0 0
BMXPQP6 FILE v-G---- --- 0 0
BMXPQP6 DIRECTORY ------- --- 27449 3513472
BMXPQP6 DIRECTORY ------- del 612 78336
BMXPQP6 DIRECTORY --G---- del 0 0
BMXPQP6 DIRECTORY -nG---- --- 0 0
BMXPQP6 DIRECTORY -nG---- del 0 0
HVUDRTK FILE ------- --- 0 0
HVUDRTK FILE ------- del 0 0
HVUDRTK FILE --G---- del 0 0
HVUDRTK FILE -nG---- --- 0 0
HVUDRTK FILE -nG---- del 0 0
HVUDRTK FILE v------ --- 0 0
HVUDRTK FILE v-G---- --- 0 0
HVUDRTK DIRECTORY ------- --- 0 0
HVUDRTK DIRECTORY ------- del 0 0
HVUDRTK DIRECTORY --G---- del 0 0
HVUDRTK DIRECTORY -nG---- --- 0 0
HVUDRTK DIRECTORY -nG---- del 0 0
THJTAAV FILE ------- --- 526381 847518722098
THJTAAV FILE ------- del 6113 0
THJTAAV FILE --G---- del 47 0
THJTAAV FILE -nG---- --- 0 0
THJTAAV FILE -nG---- del 0 0
THJTAAV FILE v------ --- 60 0
THJTAAV FILE v------ del 0 0
THJTAAV DIRECTORY ------- --- 27440 3512320
THJTAAV DIRECTORY ------- del 599 76672
THJTAAV DIRECTORY --G---- del 0 0
THJTAAV DIRECTORY -nG---- --- 0 0
THJTAAV DIRECTORY -nG---- del 0 0
THJTAAV DIRECTORY v------ --- 9 1152
BVTQQPI FILE ------- --- 460087 839865216370
BVTQQPI FILE ------- del 5308 0
BVTQQPI FILE --G---- del 0 0
BVTQQPI FILE -nG---- --- 0 0
BVTQQPI FILE -nG---- del 0 0
BVTQQPI FILE v------ --- 66336 0
BVTQQPI FILE v------ del 11 0
BVTQQPI DIRECTORY ------- --- 24629 3152512
BVTQQPI DIRECTORY ------- del 548 70144
BVTQQPI DIRECTORY -nG---- --- 0 0
BVTQQPI DIRECTORY -nG---- del 0 0
BVTQQPI DIRECTORY v------ --- 2819 360832
BVTQQPI DIRECTORY v------ del 4 512
QLFSI6G FILE ------- --- 526441 847580937619
QLFSI6G FILE ------- del 4 0
QLFSI6G FILE --G---- del 0 0
QLFSI6G FILE -nG---- --- 0 0
QLFSI6G FILE -nG---- del 0 0
QLFSI6G FILE v------ --- 0 0
QLFSI6G DIRECTORY ------- --- 27449 3513472
QLFSI6G DIRECTORY ------- del 1 128
QLFSI6G DIRECTORY -nG---- --- 0 0
QLFSI6G DIRECTORY v------ --- 0 0
syncthing debug database-file v3frg-au6mt trinity-samples.zip
DEVICE TYPE NAME SEQUENCE DELETED MODIFIED SIZE FLAGS VERSION BLOCKLIST
-local- FILE Audiosoftware/Alchemist (Trinity To Triton)/trinity-samples.zip 3271757 --- 2022-03-16T18:52:42.7549393Z 41680330 --G---- BMXPQP6:1758805844 Fi2Sb1ZW
BMXPQP6 FILE Audiosoftware/Alchemist (Trinity To Triton)/trinity-samples.zip 3258271 --- 2022-03-16T18:52:42.7549393Z 41680330 ------- BMXPQP6:1758805844 Fi2Sb1ZW
THJTAAV FILE Audiosoftware/Alchemist (Trinity To Triton)/trinity-samples.zip 3279284 --- 2022-03-16T18:52:42.7549393Z 41680330 ------- BMXPQP6:1758805844 Fi2Sb1ZW
BVTQQPI FILE Audiosoftware/Alchemist (Trinity To Triton)/trinity-samples.zip 3292688 --- 2022-03-16T18:52:42.7549393Z 41680330 ------- BMXPQP6:1758805844 Fi2Sb1ZW
QLFSI6G FILE Audiosoftware/Alchemist (Trinity To Triton)/trinity-samples.zip 3410503 --- 2022-03-16T18:52:42.7549393Z 41680330 ------- BMXPQP6:1758805844 Fi2Sb1ZW
-local- FILE Audiosoftware/Alchemist/trinity-samples.zip 3271758 del 2025-09-25T13:12:39.7549393Z 0 --G---- BMXPQP6:1758805959 -nil-
BMXPQP6 FILE Audiosoftware/Alchemist/trinity-samples.zip 3258272 del 2025-09-25T13:12:39.7549393Z 0 ------- BMXPQP6:1758805959 -nil-
THJTAAV FILE Audiosoftware/Alchemist/trinity-samples.zip 3279285 del 2025-09-25T13:12:39.7549393Z 0 ------- BMXPQP6:1758805959 -nil-
BVTQQPI FILE Audiosoftware/Alchemist/trinity-samples.zip 3292689 del 2025-09-25T13:12:39.7549393Z 0 ------- BMXPQP6:1758805959 -nil-
johannes
June 7, 2026, 8:42pm
4
It turns out that the client was indeed extremely busy and just stopped exchanging information about these files with the other clients. Now after updating to 2.1.1 they are all up-to-date.