I have records from 2012 (successfully imported from previous Maxthon versions). Only a couple of months of records are being imported and definitely not even 720 days. I also tried freshly extracting 32bit (maxthon_portable_6.1.2.2600_beta_x86) as well as 64 bit (maxthon_portable_6.1.2.2600_beta_x64) portable versions into new folders and tried importing installed MX5 guest account from scratch but again and again same result.