After exporting i can't hear some instrument's sounds

[CB]

I can't hear some instrument after exporting (in wav format). my asio is 'FL studio asio'.

 

[57Gregy]

Welcome to the forum.
Are the 'instruments' audio, MIDI or a combination of the 2?
Are you using any software synthesizers? Or a hardware synthesizer such as a MIDI keyboard or MIDI sound module?
What is your audio interface or sound card?
What format is the export (Tracks, Busses, Entire Mix, etc.)?

[Byron Dickens]

And get rid of that garbage FL studio driver.

[John Vere]

On 4/16/2023 at 10:36 AM, Byron Dickens said:

And get rid of that garbage FL studio driver.

+1 to that. It’s been found to be invasive and interferes with other drivers. It gets installed with their software just like the other pesky Steinberg generic driver. You need to delete them in Reg Edit.  Then use WASAPI shared mode if you don’t have a proper interface.  
But that said I would guess it’s because you didn’t set up the export dialogue properly A screenshot would be useful. 

Edited April 18, 2023 by John Vere