Had that happen after updating my element mgr on an SU update. That issue was addressed by Nortel and you can retain them now.
Also, if your IT network does remote updates, especially security updates on your pc; it has wiped it out too. Usually after it prompts you 'do you want to restart your computer?' Same flippin' updates usually bung up my autocad LT too. Do you have admin rights on your pc or just user?
I usually keep an additional copy of summary.xml on my computer in cause the next SU, element mgr, and cartridge install wipes it out.
KE407122
What was I thinking?
A.G. Bell