If you are using one file to record your data, this may corrupt your data, there is not guarantee that it can be recovered. What I would do is try to have shorter runs of data and get PicoLog to repeat immediately creating another file with a number at the end of it.
This way if you do loose data it would only be the last file you had.
If your data is corrupted send an email to firstname.lastname@example.org
, with the bad file and a good file.
Hope this helps.