Fixing missing modification times on Windows 11 files

[severy]

Now that I have been running FreeFileSync a number of times on my new Windows 11 laptop, I'm finding that it keeps recopying the same old files over and over again. When I dug into the issue, I found that the files that were being copied had a blank modification time on the original drive. So when they are mirrored by FreeFileSync, it shows the error "Cannot write modification time... A FAT volume can only store dates from year 1980 to 2099!... Modification time 1970-01-01 00:00:00 GMT". That error makes sense, but the problem is that the date modified on the mirrored file is now set to today, so the file will always be different on every sync run and will be recopied over and over again indefinitely.

How can I do a bulk fix of the missing modification times on the original files so that this problem doesn't keep happening over and over again? I would be fine with setting all of the missing modification times to the creation time of each file, but I haven't been able to find a utility that would perform that function.

[xCSxXenon]

Powershell

[therube]

I haven't been able to find a utility that would perform that function

What have you tried?

1970-01-01

From what I can tell, a file dated before 1-1-70 displays with no date - in Windows Explorer.
It does still have a date, it is only that Windows Explorer does not display it.
(At least in Win7. And seemingly so in Win11. Kind of telling how Windows has "advanced" during the years, no.)

I would expect any real file manager, or any date changing utility to be able to manipulate the date.
A (unix-like) touch utility certainly can. As can (Nirsoft's) BulkFileChanger.

[therube]

the files that were being copied had a blank modification time on the original drive

I wonder if there is actually a "NOT" date (instead of a date < 1-1-70)?

Using a file date 12-31-69, that date does show up as 12-31-69 in FFS (& even though it shows as blank in Windows Explorer). Likewise, the sync'd file is also dated 12-31-69.

And on a subsequent Compare, it does not report anything to do (as in it is not finding anything to sync, again).

1. FFS shows a date of 12-31-1969. (Windows Explorer does not show a date.)
2. FFS copied same, still with a date of 12-31-1969.
A subsequent Compare does not find anything more to do.
.

FFS undated file successfully copied.png (72.24 KiB) Viewed 543 times

[severy]

BulkFileChanger did the trick, thanks, therube! Once I set the missing modification dates to the creation date, FFS was able to sync the files without any errors.