I recently had a catastrophic episode with my hard drive resulting in an inadvertant reformatting. I used a program (EasyRecovery) to try and reconstruct the files on the drive, which was generally successful, and I copied everything to a new drive keeping the original drive untouched. However, a few of my Sidekick Cardfiles were partially scrambled (as an aside, database-type files seem to be the most susceptible to corruption even without drive crashes).
These files were critical to me as I had several years of client contact information (allright already, I should have performed frequent backups). Luckily, the rolodex pane for the cardfiles (left side of the screen) was totally intact (this was key in terms of subsequent recovery) but I noticed that while progressing through the cards, I would eventually reach a point where the card data (right side of the screen) contained garbage.
Recreating the cardfile requires a program that can read the drive on a sector-by-sector basis and a program that can write chosen sectors to a file (preferably on a floppy disk or different drive) as well as append sectors to the file, thereby building the file step by step. I found that Acronis Disk Editor was a good choice for easily and quickly browsing sectors of a hard disk--data in hex form is shown on the left side of the screen (you can ignore that) with ascii text on the right. Since I was using SideKick 2.0, all *.sdb files begin with "SKW200" (other versions of Sidekick undoubtedly have similar identifiers).
So I would have Sidekick opened with a copy of the "corrupt" cardfile and I would use the Acronis search feature to scan the original drive for "SKW200". I discovered that there were sometimes several copies of the same cardfile on the drive (although slightly different versions) so you need to make sure you find the correct (most recent) version. This is where having Sidekick opened is important. The layout of data in each of my cards was lastname, firstname, company, etc. Let's say that scrambled card data started with the card having Davis as the lastname. Starting with the sector that had SKW200, I would move forward sector-by sector until the data became gargage. If this occurred at the "Davis" card, I knew I had found the right file and version.
From this point, recovery is fairly easy. Write down the sectors (starting with SKW200 and ending with the last good sector, in this case Davis would be within that sector). You should also note the text in the end of the last good sector which could be anything. Let's say the last good sector contains part of Davis' phone number--e.g., (213)777-56. Then use the search feature to find the sector with the next name after Davis (let's say it was Edwards). When Acronis finds the text "Edwards", move back so that you can find the beginning sector that should "splice" to the previously found last good sector. In the example I gave, this should be the final two digits of the phone number. So this is the beginning of the next good group of sectors--note down the sector number. Continue the process by moving forward again until you reach garbage and note the last good sector and the lastname contained in that sector--note that sector number and the text it contains, etc, etc.
In one of my cardfiles, the data was split into six different groups of sectors and in the other cardfile the data was split into two groups.
Having written down all the pertinent sector information, I recommend using Norton Disk Editor in Dos mode (boot from a floppy) to gather the sectors and write to a file. During this process, Norton should display sectors just as Acronis did, but Norton allows for building of a file by appending data in chunks.
I was 100% successful in recovering the corrupted *.sdb files with this method, and it is easier to do than to explain. I suspect that most of you are wiser than me in terms of remembering to backup data so this type of nonsense can be avoided. But it's good to know there are tools and procedures to recover data.