Can no longer save Custom UI settings.

For whatever reason, I can no longer edit any custom user windows, add buttons to them, or modify them in any way.

I was only able to fix this by deleting UserButtonToolSettings.xml  ,  but there is quite a lot of buttons I wish to keep, and I would rather not build everything from scratch.  It is 5mb big....

any suggestions to fix this? 

thanx.

Can you send me your config files?

https://www.dropbox.com/s/ymwiu06yhkcfh5f/User%20Settings.rar?dl=0

Try this
http://www.digitalfossils.com/Download/NVil-Jan-22-17.rar

Seems to work!  Thankyou!

How would you suggest I manually delete the custom windows which are uneccessary...

You can't delete them. You can empty and hide them.