So your microsoft SyncToy Echo Isn't Deleting Files from the right folder (right hand side) ?
I have seen this going on a few forums and i don't understand why people can't get there heads around it.. so i shall try and explain.
When you select Echo mode you MUST start with an Empty Folder (the right folder must be empty)
There is a perfectly good reason for this, one such as it stops synctoy from ever removing a pre-made folder on a drive, like as system restore, recycle bin, hive file and so on.
SyncToy also Creates TWO files when you create a folder pair.. One in the Right side & One in the left. They both hold a list of the contents of the folders/drives and there sizes. This is why SyncToy knows a files and amount of files and sizes on the Right has changed in comparison to the file on the Left (without having to tick the "check files contents" option) which actually when ticked (it takes longer to scan) because it does an MD5 compare on both sides, handy incase a files size is the same but corrupt.
It scans so fast without it due to the TWO dat files it creates
IF you started with the RIGHT side having any contents (THEY'LL NEVER BE MODIFIED) You MUST START with an Empty the right side AND delete BOTH the dat files and then re-create the Folder Pair SetUp from scratch.
The dat Files look like this, it should stand out.. its the one file that wasn't originally put in any folder by you.. Note the Numbers in your file wont be the same as mine, but the two file(s) will look like this