can't restore registry (XP)

Trying o restore my registry backup and keep
getting "cannot import. not all data was successfully
written to the registry. some keys areopen by the system
or other process".
I have stopped all the processes except the bare min,
what's happening here?
The problem started when mcafee support told me to edit
the registry to complete the uninstall. That caused a lot
of problems and now I can't restore the registry backup I
made.
any suggestions on how to fix this?