Make sure Picasa is closed before proceeding with these instructions.
Run a search for: catdata_info.pmp
1. Click "Start."
2. Click "Search."
3. Click "All Files and Folders."
4. Make sure the search is set to "Look in:" Local Hard Drive (C:).
5. Click "More Advanced Options" to check the "Search Hidden Files and
Folders."
6. In the "All or part of file name" field, enter: catdata_info.pmp
7. Click "Search."
"Delete", then click "Yes." When you open Picasa again, none of the
Collections including Hidden folders will require a password to access.
Or traverse the folders in your profile on windows. Complete path can be like C:\Documents and Settings\'your profile id'\Local Settings\Application Data\Google\Picasa2\db2>. Delete the file catdata_info.pmp and the password for hidden folders will be cleared from Picasa.