I've faced this kinds errors previously. Its something that you cannot do anything with that crashed table. So the better way to recover is just have a full backup of the entire database except that table. Then create a new database & import that backup. Then try to upload that crashed table into the new database from any of your local backup.

Hope this helps. This is the way that I've followed to recover.
Note: I was trying to recover the table from mysql table recover tools but nothing happens.

Rony

Thanks Rony, I'll try that!

That's really not necessary.
Just run mysql through SSH or other command line interface, then SELECT DATABASE your-database-name;

For example, on my local backup server, my procedure would be:
mysql -uroot -p
<then it's gonna ask me for a password>
<after that, I'm gonna enter my password and press enter>
then I would type
SELECT DATABASE concrete5;

aaaand finally execute
REPAIR TABLE `PageSearchIndex';

So, to sum it up:
mysql -uroot -p
SELECT DATABASE concrete5;
REPAIR TABLE `PageSearchIndex';
That's about it.
If you use a shared hosting and/or don't have the means to execute such a command, have your hosting provider do it.

I was trying to do that anyway in my case but not succeeded. It doesn't recover the table. So I suggest him an alternative way.

Rony

Should have tried REPAIR TABLE tbl_name USE_FRM;

The USE_FRM statement is important sometimes. It acts very differently (pretty much does truncate->restore automatically), so you should try the first method before the USE_FRM method.

OK thanks. I'll check this approach first, remembering obviously that I've never looked at a MySql database before!