I'm running Windows 7 Home Premium SP1, 64 bit.

The initial problem is that I can't get the 'necklace' category to show in CTU. So I decided to start from scratch and created the folders as instructed here:
Sims 3:CTU Guide>What do I need?
But when I click File>Options>Change folder to change the 'root' and browse to the newly created folder as instructed above, the displayed file path doesn't change.
I don't know if the .net framework has anything to do with this problem, as CTU appears to be working properly in every other way. But just in case, I went through the steps of downloading and trying to install first .net 2.0 which gives me a not compatible error, and the .net 3.5 installer doesn't do anything when I double click it.
So, how do I change the Sims root directory, and/or is it even possible for CTU to display/clone necklace accessories?
Thank you in advance for your kind consideration.

Have you tried it witth s3OC?
You can clone the file with S3OC and edit with CTU imo
http://www.den.simlogical.com/denfo...php?topic=190.0

CTU can't be used to set accessories to the necklace type - it understands the field, but there's simply no checkbox for it in the UI. You'll have to do that manually in S3PE (Which takes all of 40 seconds).

If you still need to change the root directory, try enabling Debug Mode in the File menu, then restarting CTU - also bear in mind that after changing the path, you may need to restart CTU to see the path change. If that doesn't work, it could be a UAC problem - did you install CTU into Program Files or somewhere else?