I use a post-installation script for Ubuntu that installs several packages. This script installed "unity-tweak-tool" and "indicator-multiload" that have as dependency several Unity and indicators packages. After I removed those two packages, all the unused dependencies and a relogin, the indicator icons came back.
Ok, I found the source of the problem:
I use a post-installation script for Ubuntu that installs several packages. This script installed "unity-tweak-tool" and "indicator- multiload" that have as dependency several Unity and indicators packages. After I removed those two packages, all the unused dependencies and a relogin, the indicator icons came back.