Urgent BUG: FFS 'updating' different files - same name different size

[sentry1]

Hi,

FFS has started doing something strange. I select the comparison to be "File name and File Size" but it is ignoring File size.

This is truly dangerous as it wants to overwrite files in one folder with completely different files in another (they have the same name as some are photos from an iPhone 5 and some are photos from an iPhone 6).

If I had trusted FFs and clicked "Sync" I would have lost a whole bunch of photos.

What is going on? Do I have the config set wrong somewhere else? I noticed this today on FFS 7.2 and it is doing the same thing now I have updated to FFS 8.6.

The two folders I am comparing are both on a WD My Cloud NAS.

Thanks,
Sentry1

[Zenju]

Do you have some detailed information that demonstrates this behavior?

[sentry1]

https://postimg.org/image/jpc8297bd/

[sentry1]

I hope the above image demonstrates a different filesize, same name, being updated right to left (I always want the earlier version of a file in this context).

[Zenju]

You're using "two-way variant"? In this case the files on the right hand side have changed since last sync, so they will be copied to the left side.

[sentry1]

I'm using Custom. I am organising a mess of photo upload folders. Sometimes when the photos were uploaded into these folders using various apps/ftp etc, the original date was not preserved but was overidden by the upload date. Therefore I am using FFS to collate all the photos into one folder and I have am using "custom" to 'keep' photos which have the earliest date (as this is likely the date the photo was taken rather than an upload date).

This isnt really the issue. In general this works well.

The primary problem is that two different photos have the same filename but different sizes. However as you can see from the link, FFS is NOT recognising that they have different file sizes. FFS want to overwrite the file on the left with the file on the right. This is clearly not correct as they are very different files.

Is that clear or shall I try to explain another way?

Thanks for your quick help by the way!

[Zenju]

Why are files with different sizes being updated a bug in FreeFileSync? Item association is assumed when finding a path match.

[sentry1]

The comparison is "File Time and size". It was my assumption that FFS would look at two files and go through this logic:

1) Is the name the same? No = NO MATCH, Yes = possible match, continue
2) If the filename is the same, is the size also the same? No = NO MATCH, Yes = DEFINITE MATCH

Therefore, if the algorithm reaches a state of definite match for Name and Size, then it acts accoring to my synchronisation setup -> If the file is the same, but the dates are different, then please use the EARLIER DATE as the master.

However, what it is doing is this:

1) Is the name the same? No = NO MATCH, Yes = DEFINITE MATCH

Therefore, one photo called IMG_001.jpg from one iPhone is overwriting (effectively deleting) a totally different photo, which is also called IMG_001.jpg from a differnt iPhone.

The fact that the sizes are different should, in my view, alert FFS to treat them as different files and COPY the file in question to the new folder (perhaps requesting a new name) rather than UPDATING.

I'd be interested (now that you know what I'm trying to do) to learn whether I should be using a different configuration to do what I need here.

Thanks!
Sentry1

[sentry1]

Anyone else got thoughts about the best way to do this if FFS can't do what I need?

Thanks in advance,

Sentry1

[Zenju]

A rough overview of FFS's pair finding algorithm: https://freefilesync.org/manual.php?topic=comparison-settings

[sentry1]

Thanks for that.

For clarification, does option III (Compare by Filesize) include a check on the name too? So it doesn't just use file size on its own?

thx

[sentry1]

I'll give it a go when I can to find out.

Got to say I'm a little nervous about what I may have already lost :-(

Thx,
Sentry1