I have come across a manual method of repairing (rebuilding) the Picasa database.
The database file is the "Picasa2" folder located at one of the following locations.
For Vista: C:\Users\[useraccounthere]\Applciation Data\Local\Google
For XP: C:\Documents and Settings\[useraccounthere]\Local Settings\application data\google
Note you may have to show hidden files/folders in Windows Explorer to see the above folders.
To rebuild the data base you have to
- Shutdown Picasa.
- Then browse to the above location. I recommend renaming the "Picasa2Albums" and the "Picasa2" folder to something like "Picasa2Albums.saved" and "Picasa2.saved" in case you need to put the older database back.
- After that you can start Picasa and it will recreate the database files. I ran this on a pc with over 10,000 pics and it took under 1 hour to rebuild the database.
The above process should not affect any edits you made to your pictures or the pics themselves but as always its a good idea to take a backup of everything important to you just in case.
For backup tips see 7 Ways to Backup your data.
There are other ways to achieve this but ItFixed it for me.