When I was trying Picasa2 features I found that it can protect specific categories by password, I set a password, after a while I forgot it!!!! I tried google to find password recovery for Picasa2, but there was nothing on the web, to be honest, I didn’t search too much because I was almost sure that I can solve it 😉
Anyway, This might help you to recover your Picasa2 category password.
1. Open this folder on your computer:
[localUsernameProfile]\Local Settings\Application Data\Google\Picasa2\db
2. Remove (Or Rename) this file: catdata_info.pmp
3. Open Picasa2
4. Change the password of that category
5. Exit from Picasa2
After that you will find another catdata_info.pmp in that folder
Have Fun!!