Comparison using file Created vs Modified date?

Posts: 21 · databoxer 15 Feb 2020, 00:03

I have been using FFS regularly for a long time to sync between my Win10 laptop and my NAS. It has always worked great, and I love it. Today, for the first time, something odd happened, both with version 10.19 and 10.20 (which I downloaded to see if it would fix the problem). Mind you, this has been working fine for years. However, today FFS seems to have started using the file Created date for comparison, not the file Modified date, but only for SOME files! Very strange.

This is a problem because when I set up my new laptop last year and copied files over from a backup, the Created date is when I copied the files, while Modified (which is what I want and what makes sense to me) is earlier for these files, by several years in many cases. So today a handful of files showed up as needing sync due to this new issue, but they have the same file name, size, and Modified time/date, and they have been comparing as identical just fine for months or years on the same local drive and NAS, even earlier today. I am not aware of having done anything differently or changed anything today.

I looked for a setting in Options as to which file time to use in Comparison, but I don't see one. I am very baffled why this just started now, and even more so as to why it is only on some files, not all of them.

Help! Thanks for any help you can give.

Posts: 21 · databoxer 16 May 2023, 02:05

This happened to me in 2020 on an old laptop, then it worked fine again until today. It was working fine even this morning, then this afternoon the weirdness came back. I tried it on three different laptops, with FFS v12.1 and v12.2. Very strange. I'm not sure if something changed in FFS or in Windows or what. Help!

Posts: 4056 · xCSxXenon 16 May 2023, 15:43

Can't say I have ever seen this issue...
When you run a comparison, you can check why FFS has determined a file need to be synced.

Posts: 21 · databoxer 16 May 2023, 16:03

Thanks for your response. Yes, it's very strange. FFS decides that it needs to sync the file because it (incorrectly) sees mismatching dates on two files, one on the NAS and one on the USB drive. As a specific example, in the difference list after running an FFS Compare op, FFS shows a NAS file with a date in 2011 (i.e., an old file), but the corresponding file on the USB drive is listed by FFS with a date in 2020. I bought this USB drive in 2020, formatted it to NTFS, and copied all the files over from the NAS. I run FFS using Mirror mode occasionally to compare/sync from the NAS to the USB, which serves as a backup of the NAS. Windows Explorer shows the Created date for this file on the USB drive as 2020 (which is what I would expect), but the Modified date is the (correct) 2011 date. I would be happy to share screenshots, but I don't see how do that in this forum.

Somehow FFS has decided to use the Created date instead of the Modified date. There are thousands of such files with Creation dates in 2020, but strangely FFS only seems to make this mistake on some files/folders, not all. It's quite baffling. If the wrong date were being used on the NAS version of the file, I might suspect the NAS OS / file system, but it's on the NTFS USB drive, formatted and used only on Windows, which is where I am running FFS.

As I mentioned, this happened once a few years ago, on an older USB drive, and then it worked fine for a few years. Just yesterday the problem showed up again.

Posts: 4056 · xCSxXenon 16 May 2023, 16:31

"Editor & Preview" for pictures.
I see what you're saying. You didn't specify what FFS says the mismatch is though. You said "FFS decides that it needs to sync the file because it (incorrectly) sees mismatching dates on two files", but what are the two timestamps it is seeing specifically? It should tell you the exact time and date when hovering over the action icon in the middle.

: 2023-05-16 12_26_34-C__Users_j.lewis_Documents_sync_OneDrive.ffs_batch.jpg (73.96 KiB) Viewed 672 times

If you could get that to pop up for one of the offending files, post a screenshot of the popup along with the properties windows for each copy of the file, NAS and USB. Obviously, don't perform a sync before doing that. Maybe the timestamp FFS reports doesn't match either 'created' or 'modifeid'

Posts: 21 · databoxer 16 May 2023, 17:16

Attached are two screenshots in a PDF file, showing the FFS compare results for a file, then the Windows Explorer file properties for that file. You can see that the Modified date in Explorer does not match the Date shown in FFS, which uses the Created date instead.

FFS_screenshots.pdf: (484.71 KiB) Downloaded 60 times

Note that I am using Mirror mode for synchronization, so any difference in name/size/date will cause the file to be copied from the NAS to the USB drive. As an experiment, I tried changing to "Two way", but it also saw a miscompare (and wanted to copy the other direction).

Here is what is very strange: after I went into Windows Explorer to view the file properties, showing the Created/Modified dates to get the screenshot, I then ran another FFS compare, but the file wasn't in the sync list any more! That is, merely viewing the file property seemed to fix the problem!! Maybe this is a strange Windows issue? (My engineering team used to call this kind of behavior a "Heisenbug" <g>). Now I'm really baffled. Any thoughts?

Posts: 1038 · therube 16 May 2023, 18:29

It might be your NAS.

Recurring "Updates" That "Don't"

And this, in particular, viewtopic.php?t=7396p24922#p24924.

Posts: 21 · databoxer 16 May 2023, 18:34

Thanks, but I don't see how the NAS could cause incorrect dates on the USB drive. If the incorrect date were on the NAS files, I would definitely suspect the NAS. It's even less likely to be the NAS, given the strange behavior I just saw where the act of viewing the file properties in Windows Explorer fixes the problem.

Posts: 4056 · xCSxXenon 16 May 2023, 19:43

Not necessarily a problem with the USB. Although your thinking makes sense, odd behavior on the USB only and viewing properties of the file on the USB fixing it, that doesn't mean the original copying from the NAS to the USB didn't have an issue itself. It could be a network glitch that happens very infrequently, causing metadata corruption, or a NAS OS bug, or maybe the files themselves are not fully intact, or a bad drive, or a bad internal cable, so many possibilities!
First and foremost, make sure the NAS is up to date

Posts: 4056 · xCSxXenon 16 May 2023, 19:45

And I noticed that they are all zip folders? I see some other files, but those aren't updates/differences, they just haven't been copied to the destination yet. Maybe it is only occurring with zip

Posts: 21 · databoxer 16 May 2023, 19:53

No, they aren't all .zip files. It has happened with a bunch of different files and file types, and it seems to change sometimes from Compare to Compare op. My Synology NAS has the latest version of its DSM OS installed. If the USB directory entries were somehow corrupted during the initial copy (done under Windows), I would have expected this behavior sometime over the past few years, when I have used FFS sync regularly.

Thanks for your suggestions. This strange case may have to remain a mystery. :-(