When running MS SyncToy and echoing one folder to another, I find that the program does not delete folders which are not present in the "original" folder when backing up to a thumb drive. This leads to unwanted proliferation of folders, as the not-deleted ones get copied back again when syncing in the other direction...

Anyone have any ideas? Is SyncToy the wrong tool after all? Thanks!

  • Which version of SyncToy ? 1.4 or 2.0 ?
    – Gnoupi
    Aug 19, 2009 at 8:24
  • :) Aug 19, 2009 at 8:38

4 Answers 4


From SyncToy 2.0 - Frequently Asked Questions

Q. SyncToy 2.0 appears not to sync deleted files when I have the sync option set to 'Echo'

A. This can happen if the files are updated on the right. This includes if the file was touched by an anti-virus program, music player, etc. To confirm that this is indeed the case - change the sync option to "Synchronize" and do a "Preview" sync. Do NOT hit run because this will sync changes from the right to the left. If on a preview you see updates from the right to the left folder, this means it was changed on the right. The only workaround in this case would be to manually delete the file on the right. And do not forget to change your sync option back to "Echo".

I'm guessing this is your problem, because I just checked on my computer, the "Echo" deletes folders correctly.

Precisions on the "Echo". The "Echo" method in SyncToy will echo the changes from left to right. But to avoid losing data, it won't take care about folders and files created after. Typically, in your case, you want it to delete the folders you created after, but in general, I doubt you expect the backup tool to erase data it's not supposed to take care of.

  • So if the folder was created later, it won't be deleted? Any workaround that you know of, short of deleting everything and copying it all from scratch? Aug 19, 2009 at 8:38
  • 2
    I have to say, I have had a world of hurt with this program. (In particular, silently not updating folders at random). Not recommended! Feb 4, 2010 at 8:28

SyncToy may be fine for bidirectional sync, but the 'echo' mode is seriously flawed in my opinion. It doesn't do what you expect. I assumed the echo mode would work like this. You've specified a one directional copy from left to right. So you're saying the left side is the model for what you want. When you run the program you expect it to do everything necessary to the right side to make it exactly the same as the left. This would includes overwriting files in the direction left to right and deleting anything that shouldn't be present on the right. In other words the overall effect should be the same as if you had deleted everything on the right and copied it afresh from the left. The documentation seems to support this.

From my experiments the program doesn't work like that at all. There are two gotchas.

(1) It will only copy files from left to right if the left version is newer. If the right version is newer it doesn't copy that file and fails to warn you.

(2) It will not delete anything from the right unless it had previously been present on the left and then deleted from there. So a file or folder that you added directly to the right remains there forever. Again, it fails to warn you.

So it's not producing a perfect mirror at all. In fact, what it produces seems of dubious value. It's certainly no use as a backup, since you may have different versions of files on the left and right sides. Microsoft allude to this (but don't fully explain it) in the FAQ mentioned by Gnoupi.

They suggest a workaround by previewing what would happen if you synced the other way and then manually altering the files, but this is far too much work. Joel in Gö is right - it's the wrong tool for this job.


Use Empty Folder Nuker to clean up the empty folders left by SyncToy.


So I've encountered the same problem all these years later.

Unfortunately in Echo mode you cannot mess with the Right hand folder with Synctoy for any reason, otherwise it becomes chaotic.

I found Allway Sync to do the job for me. Simple GUI, if a little backwards, but with more intelligence. If it finds additional, missing or modified files on the right, then it will delete them on the right. It's much more like a mirror than Synctoy. Further options exist such as Emailing upon error, command line etc.. etc...

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