Hi

My system restarted when my download was about 90%. after restart it started at 0% is there any way to recover the lost data?

Did it error or try to start downloading again?
If it was the same location you can right click -> Local Files -> Force Recheck
This will try to recreate the bitfield of HAVEs matching the hashes for the data.

If for some reason it has not you can use right click -> Local Files -> Location -> choose folder there

(This state happens because Tixati updates its temporary DAT files every 12-20 mins depending on load). So your state when you started again was from the last temporary backup. not to be confused with .lastgoodload.dat each time you start tixati)