Tried various pst recovery tools.
The pst file just has thousands of This is padding!!
lines in it.
So no chance in recovering that.
I'am just surprised that a pst file backed up at 4.20 am, when nobody is in the office, gets a bad compare at 8.05 am is marked 'corrupted' and then is not properly on tape.
I have more then 10 of these, so it's no just 1 file.