Fresh setup with 2 devices, sync stuck with no progress

I’m observing a weird log line when syncing between two other devices, not related to the initial post. But this time, the sync seems to work okay.

Folder F shared between A+B (id “n4q4z-ohpfz”)

A: Windows 10-1903 x64, Syncthing v1.3.4

B: Linux amd64, Syncthing v1.3.4

A has a suspicious entry in the log:

2020-02-05 14:04:49 Syncthing should not run as a privileged or system user. Please consider using a normal user account.
2020-02-05 14:04:50 Stored folder metadata for "n4q4z-ohpfz" is 723h26m4.8138797s old; recalculating
2020-02-05 14:04:50 Index for nonexistent folder "n4q4z-ohpfz"

Maybe the log is related to the problem? I don’t see why the metadata should be old. Why do I get the log line “Index for nonexistent folder “n4q4z-ohpfz”” because of a non-paused folder which seems to be fully in sync between the two online devices A+B.

Going to build a windows stindex.exe …

go run build.go -goos windows -goarch amd64 build all

stindex.exe (9.9 MB)

A: Command line (Windows):

stindex --mode idxck "X:\index-v0.14.0.db" > "X:\stindex_result.log"

Hmmm… stindex this time doesn’t output anything which implies the database is okay. I expected it to show errors for device A (like it did in the initial post’s case between those linux devices). Not sure if we diagnose the “same” problem here.