Labview can't exit in task manager because of USB-Serial

[avater]

Hi,

I encounter a problem that my labview program which just plays with the USB-RS232 port can easily go to NO-RESPONSE.The worse thing is that I cannot even kill the Labview process in task manager.The ONLY way is to restart Windows,log out doesn't work.

The program code is reading/writing the modem line state of the serial port.I don't forget to CLOSE/RELEASE any references/handles in the code.

Any ideas?

Thanks.

[RTSLVU]

Having had the same problem (USB serial port just gong off into La La land and only a reboot brings it back)

I tried everything, even posted code here and nobody could come up with a reason it would just quit working.

Changeing to actual PCIe card based serial ports fixed it.

Turns out the USB to Serial adaptors I was using were probably counterfeit 

http://www.prolific.com.tw/US/ShowProduct.aspx?p_id=155&pcid=41

FTDI also has been a victim 

https://thecounterfeitreport.com/product/562/FTDI--Chip-FT232RL-Chips.html