How long will it take to flash a51_dtul?

Dear support;
I received following firmware from xtc2 support and tried flashing XTC2 software but it is about 3 hours and still not finished.I’m sure it’s not normal.I see no progree bar on device display but soft progress bar is moving very very slow.
Is it safe if i stop the process?
Besides i tried to install rom via sd card but phone said fail to flash coz of large file size.How can i safely flash this zip file please?

Code:

0PFJIMG_A51_DTUL_L50_DESIRE_SENSE60_MR_hTC_Asia_India_2.10.720.1_R_Radio_01.01.010_U10305041_08.01.50512_release_453048_signed_2_4