Please provide us more information:
https://winscp.net/eng/docs/troubleshooting#timestamps

After changing my website host from a local provider (same time zone) to a distant provider (in another time zone) the Synchronization Checklist behavior has changed.

When I used this feature with the local provider only the files I have updated were checked (and I believe had blue arrow) so after a quick glance at the list I simply clicked OK.

Now with distant provider all boxes are checked and I have to Uncheck All (and all either red or green). Then I laboriously check the boxes that need to be updated (at least sorting by date facilitates this).

This happens even if I have just that moment completely updated all files, still all are checked.

In the Synchronization Dialog I've tried all combinations of Comparison criteria to no avail.

My local PC is Win 10, the remote host is GoDaddy cPanel (Linux).

Not sure if my question is related to this post but it seemed closely related.

krkj wrote:

Maybe you don't like to clutter the nice program with all sorts of options?

That is exactly the reason.

Oh, I am quite willing to accept that it is not the fault of SFTP or Winscp. As alluded to, maybe the cause is backup/restore (across a DST change) or zip/unzip (across a DST change). Also, when occasionally I'm on the same LAN as one of these servers, I'll use Samba and TotalCommander or xcopy/d/s for sync'ing (and this is an additional source of ambiguity in the time stamp, I think?).
The point is, this sh** happens (to other people as well, I hear) and it would be sooo nice if Winscp (even though not at fault) would help us out.

Maybe you don't like to clutter the nice program with all sorts of options?
But consider this: There is already a 2 sec. tolerance built in when Winscp compares time stamps. The 1st request simply amounts to making that tolerance a variable. (Maybe to some other user, a 2 sec. slack it too much...)
Though it would be good to be able to additionally specify a tolerance of 'modulo a few hours'.

Of course, a related request is that for rsync support that would allow to efficiently compare files by content.

SFTP protocol is strict about using UTC timestamps. So if the server is not using them, it is its fault...

Session protocol = SSH-2
SSH implementation = OpenSSH_4.7p1 Debian-8ubuntu1.2
or another host: SSH implementation = OpenSSH_4.3
Encryption algorithm = aes
Compression = No
File transfer protocol = SFTP-3
------------------------------------------------------------
Can change permissions = Yes
Can change owner/group = Yes
Can execute arbitrary command = No
Can create symlink/hardlink = Yes/No
Can lookup user groups = No
Can duplicate remote files = No
Can check available space = No
Can calculate file checksum = No
Native text (ASCII) mode transfers = No
------------------------------------------------------------
Additional information
The server does not support any SFTP extension.

What protocol are you using?

I have read the documentation about DST and related time stamp problems.
The bottom line is that often Winscp in Commands/Synchronize.../
will want to sync files even though the remote files are the same, just with a time stamp that is off by 1 hr. I've even had this problem with offsets of several hours. (Maybe SYSOP has restored files from backup somehow with a time offset?; also zipping and unzipping files can cause this: zip archives handle DST and time zone badly.)
The problem occurs in Commands/Synchronize.../
(at least) with the following settings:

Remote,
Mirror files,
Preview changes,
Comparison criteria:

Modification time
File size

Hence the requests:
* To be able to specify that a time difference less than hh hours mm minutes ss seconds be ignored.
* To be able to specify that a time difference of integer hours (not more than hh hours) be ignored.