I have ATMEL SAMV71 xplained ultra board (http://www.atmel.com/tools/ATSAMV71-XULT.aspx) and ATMEL STUDIO 7.0 software. I downloaded freeRTOS zip file and followed the steps in http://www.freertos.org/AtmelSAMV7Cortex-M7RTOSDemo.html . build was sucessfull. when i select "Start Debugging and Break" i am getting error as "unable to start program libRTOSDemo.a . the specified file is an unrecognised or unsupported binary format". can someone help me out how to solve this problem?

I don't think this is a FreeRTOS issue as such, but some kind of project or misconfiguration issue as the error message you posted appears to show you are trying to run a library (.a file extension) rather than an elf file. If you look in the "output files" folder of the Solution Explorer window in Atmel Studio you should see a file called RTOSDemo.elf - that is the file you should be executing. I have just tried this using Atmel Studio 7 and a clean FreeRTOS V9.0.0rc2 release and the file is generated correctly.

In the output files i have the file called libRTOSDemo.a file no RTOSDemo.elf was found.. Here is the steps i did, first i downloaded FreeRTOS V9.0.0rc2.zip file. then i extracted this to some folder, then i opened the extracted folder and then followed the path. FreeRTOS->Demo-> CORTEXM7SAMV71XplainedAtmelStudio -> RTOSDemo.atsln i opened it in atmel studio 7. then i connected the board to my computer, board detced sucessfully. then selected 'Build solution' from the build option, build was sucessful. when i select "Start Debugging and Break" i am getting error as "unable to start program libRTOSDemo.a ..

Those are the correct steps - and the steps I followed myself - but my output was an elf file not a library. Check the project options to ensure they are set to build an executable rather than a library.